JOURNAL OF THE OPTICAL SOCIETY OF AMERICA

Spectrum and energy levels of doubly ionized europium (Eu in)

Jack SugarNational Bureau of Standards, Washington, D.C 20234

Nissan SpectorIsrael Atomic Energy Commission, Soreq Nuclear Research Center, Yavne, Israel

(Received 6 June 1974)

The sppctrum of Eu 3EC obtained with a 6 A sliding-spark discharge has been measured from 2000 A to9000 A. Of the 890 spectral lines observed, one-third are classified in an energy-level scheme consisting of104 excited levels. These belong to the 4f7 configuration and to the 4f6 QF)5d, 4f6 (7F)6s, and 4f 6

(7F)6p

subconfigurations. Except for 4f', calculations of these configurations with least-squares-adjustedparameters were carried out. A reasonably suitable truncation for the energy matrices of each configurationwas found.

Index Headings: Europium; Spectra; Wavelengths.

In their paper on Eu II, Russell, Albertson, and Davis'reported Zeeman data for seven lines of Eu in, whichthey interpreted as resonance lines arising from4f7 8S712-4f 6 5d transitions. This interpretation wasrecently confirmed by Martin and Sugar2 by means of acalculation of the energy levels and g factors for the4fJ6 (F)Sd subconfiguration. The calculation showedsatisfactory agreement with level positions, Zeemandata, and relative intensities of the resonance lines anddemonstrated that practically all the oscillator strengthavailable for transitions from 4fQ5d to the ground levelis contained in these lines.

The goal of the present work was to locate the levelsof the 4f6(7F)5d, 6s, and 6p groups. Because this isonly a small part of 'the complete configurations, weattempted to excite this structure selectively by usinga spark excitation that barely produces Eu III. By thismeans, we observed less than 1000 lines, rather than thethousands that would be present with a more-completeexcitation. Even with this small number of lines, orperhaps as a result of it, we enountered great difficultyin making a start in the analysis. Apparently the highpurity of LS coupling in the even levels preventednumerous repetitions of energy intervals among thespectral lines that we observed.

The first breakthrough resulted from a search of theline list for the fundamental (lowest) multiplet betweenthe 4f65d and 4f'6p configurations, which is the transi-tion 5d 8 1-6p 'G. This approach required prior calcula-tions of good accuracy for these configurations. Becauseof the great amount of experimental and theoreticalwork that has been done with similar rare-earth ions,it is now possible to make very reliable calculations ofthis type, utilizing interpolated values for radialintegrals and for separations of configurations. We wereable to predict the location and fine structure of thismultiplet with sufficient accuracy to find it in theline list.

The calculations were carried out by use of energymatrices for the subconfigurations 4f0 (7F)nl. The most-

severe effect of this truncation was later found to bethe relatively poor prediction of the positions of 8Pand 6P for nl= 5d. Even after least-squares adjustmentof the radial parameters with the final energy levels,these positions were in error by -500 cm-'. Theywere finally brought into reasonable agreement by theaddition of the three ID core terms, but it is now clearthat good predictions will require more-completematrices.

About one-third of the observed lines of Eu iII arenow classified, but it may be possible to extend theanalysis with the present line list, supplemented byfurther infrared observations. Nearly all of the levels ofthe (4f5 )5d, 6s, and 6p configurations built on thelowest-core term of 4ff are known. The strong linesthat are still unclassified may be due to transitionsthat involve the low levels of 4f7 , lying at about30000-40000 cmtl. Only the 6P and the 'I of 4f9 inthis region were located.

The 6P5 12 and 'P712 levels of 4f7 have been observed 3

in absorption in a single crystal of KMgF3 : Eu2+. Bothlevels are displaced downward by -400 cm-' relativeto their positions in the free ion, apparently due to thenephelauxetic effect, which causes a reduction of thevalues of the free-ion Slater integrals.4 The effect of thecrystal environment on the 4f0 5d configuration is farmore drastic, and the interpretation of absorption tothese levels has been inconclusive, as a result of thelack of the free-ion energy-level data.5 Part of theproblem of interpretation probably arises from thefact that the p of 4f6 5d is responsible for the absorptionfrom the 8S ground level. From our present work, thisterm seems to be the most sensitive to matrix trunca-tion. A clearer understanding of the crystal absorptiondata may now be possible with the knowledge of thelevels of the free ion.

OBSERVATIONS

The single light source used to obtain the spectrumof Eu iII was the sliding spark. Operated at 6 A peak

1484

NOVEMBER 1974VOLUME 64, NUMBER 11

SPECTRUM AND ENERGY LEVELS OF Eu iii

spark current, it provided a small number of low-excita-tion lines of this ion. They were distinguished from thoseof Eu ii by observing their relative enhancement inexposures of the sliding spark at 50 A peak current.

The spectra were photographed with two similar10.7 m normal-incidence Eagle spectrographs. A vacuuminstrument containing a 1200 line/mm grating blazedat 1200 A was used for the region 2000-2600 A, andanother spectrograph in air with a similar gratingblazed at 3000 A was used for the region 2500-4000 A.A second grating in the latter instrument, blazed at6000 A, was used to photograph the region 4000-9000 A.

Exposure times were minimal, in order to hold downthe number of lines. This primarily effected the presenceof Eu ii, which easily blackens the plate at longerexposures. From 2600 to 4000 A, 10 s exposures of thespark, firing at a rate of -30/s, were measured. Longerexposure times were used at shorter and longer wave-lengths, to compensate for the lower speeds of thespectrographs and plates. The spectrum was observedfrom 2000 to 9000 A, always in first order with a platefactor of -0.78 A/mm.

The final energy-level values were adjusted by leastsquares to fit the wave numbers of the spectral lines.Using the final fit df the lines as a measure of theiraccuracy, we assign an estimated wavelength uncer-tainty of -0.003 A. Longer-wavelength measurementsdid not show better wave-number accuracy, because ofthe .wide hyperfine structure (hfs) exhibited by mostof the lines in this region. In the most unfavorable case,this amounts to a hfs width of 1.7 cm-l.

The measured wavelength values in air are given inthe Appendix. They comprise 890 lines, of which 305are classified. Five of these are doubly classified and areindicated by ditto marks in the wavelength column.The intensities are visual estimates, which are notintended to be quantitatively meaningful beyondindicating order-of-magnitude differences. Letters thatfollow intensity values -characterize the lines as:b= broad, bl= blend of two lines, c= complex (usuallyVAs), and h=hazy. The entries under classificationinclude the whole-number values of the two energylevels with a subscript J value and a superscript degreesymbol for odd-parity levels. The lower level is alwaysgiven first.

The line at 2435.135 A (2435.19 A in Ref. 1) classifiedin Refs. 1 and 2 as a; resonance line was found to beincorrectly interpreted. No level was located at thecorresponding energy and the line was classifiedelsewhere with no conflict of g factors. The measuredpattern in Ref. 1 provided that Ag= 0.290 and AJ= 1.Our classification of the line as 43 8857/2-84 9385/2', andcalculated gi=0.840 and g2= 1.128, fitted the observedZeeman pattern. The remaining earlier identifications ofresonance lines are confirmed.

ENERGY LEVELS

As mentioned, the interpretation of the spectral linesfirst succeeded by identifying the lowest multipletbetween the 4f 65d and 4f66p configurations, whichoriginates from the terms 5d 8fJ and 6p 'G. The purityof the 4f6 6p levels in LS coupling is not nearly as highas that of 4f6 5d. The coupling scheme that best suitsthe 4f 66p is Jij, the average purity of the majorcomponent of the levels being 77%, compared with61% in the LS scheme. The distribution of the 8Gcharacter among other levels of 4f 66p permitted sometransitions from them to the 5d 'H and thereforeenabled us to extend the analysis.

The identification of these few intercombination lineswas due in large part to the accurate calculation of the4f'6p configuration in advance, which rests on thehigh degree of predictability of the radial energyparameters by interpolation between fitted values fromother doubly ionized rare earths. This regularity waspointed out earlier,6 in a paper on the analysis of Tm iII.In Fig. 1 of Ref. 6, the 6p spin-orbit parameter is shownto vary nearly linearly and it is further noted that theelectrostatic parameters of 4fN6p are small and nearlyconstant for all of the doubly ionized elements in the4f period. The spin-orbit splitting, due to the 4felectrons in the 4ff configuration, is known not toaccount for the 7F intervals very well, because ofmixing with higher terms. We were able to take thisinto account adequately for the 4f16p configuration byusing only the 7F core term in the energy matrices, butbuilding in the observed splitting of this core ratherthan relying on the spin-orbit parameter, as was doneby Carlier7 for the isoelectronic Sm ii spectrum. Theonly experimental information for the splitting of the7F term is from crystal or solution data. We used theEuS+ (aquo) results of Carnall, Fields, and Rajnak' forthe level positions. These were inserted as diagonalmatrix elements of the spin-orbit interaction in a Jijscheme and then transformed to the LS scheme, inwhich all of the other interactions were calculated.

The 4f'5d and 4f16s configurations were calculatedin the same way, truncating the 4ff core to the 7F termand using the core levels explicitly in the matrices.The calculations were adjusted by fitting the radialparameters as more levels became known.

Finally, nearly all of the levels of 4f'5d, 4f16s, and4f16p that are built on the 7F core term were located.These were all based on lines observed below 3400 A.With the completion of this work, it became evidentfrom the positions of the 4f65d terms and a roughcalculation of 4f7 that at least the 6P and 61 terms ofthe latter configuration should be accessible to discoveryin the visible and photographic-infrared spectral regions.The observations were extended to 9000 A, whichrevealed 22 more lines of Eu iII and permitted the twoterms of 4f7 to be found. A further extension into theinfrared should produce more of the sextet terms of 4f7 .

November 1974 1485

J. SUGAR AND N. SPECTOR

TABLE I. Energy levels of Eu iII.

Configuration Designation J Level (cm 1l)

A f 8 Q0

6p°

6I0

4f6(7F)5d 8H(

8D

8G

BP

6p

6H

6F

TJ 34

3a

2

34481517

14

214

3445461

78-2

1421

3-2t445-2t

01

1424

34445461

74

04

14

24

34445461

24344214

21

3-

24

32445464

74

12

2432

Configuration Designation J

4f6 Q(F)6s8F

4f6 (7F)5d

4f6(7Fo)6p

4f6 (7F1 )6p

4f6 (7F2) 6p

4f6

(7

F 3 )6p

4f6

(7F 4 )6p

4f6

(7

F 5 )6p

4f6 (7 F6)6p

4f6 (7 Fo)6p

4f6(7F,)6p

4f6(7F2)6p

4f6

(7

F 3 )6p

38 229.0739 225.7140 133.12

38 050.1138 316.6638 828.5639 579.6640 518.4341 573.2242 658.2043 658.96

39 014.3639 636.8840 371.6541 159.5241 987.9042 850.07

39 769.0540 870.6042 084.25

40 897.6642 530.91

43 395.7543 885.2744 553.8045 313.7546 150.8547 069.87

46 108.7946 793.38

6G

(1,1)°1

(2,42)0

(3,2) 0

(5,2) 0

(0Q114)

(1211)0

(2,112)

(4,11)°

Level (cm-')

47 714.7449 086.13

46 096.4046 519.2647 173.3447 993.7648 925.1549 925.9650 965.29

0.00

28 200.0628 628.54

31745.9931 954.2132 073.3032 179.5532 307.7832 314.14

33 856.2234 394.4135 108.8635 972.1336 962.2938 067.3339 289.6940 659.41

35 627.36

l

Vol. 641486

4f6(7F)Sd

4f6

(7F)6s

4254

021 2

212

142434445464

0414

24344404

12

22

344454

12

212

32445464

042

14

24I1132123421

3444

44545461

14

142404

34241404

4424

544I

48 496.4349 292.5649 956.73

48 259.6248 828.9149 610.8150 805.5851 848.1852 960.08

49 905.6450 426.33

51 650.7752 099.87

78 981.86

79 437.1879 639.31

80 153.4780 253.58

81 059.4981 067.28

81 985.1382 101.85

82 954.6383 248.29

83 959.9384 486.76

84 510.34

83 009.5483 776.9884 563.08

84 640.5684 938.40

85 479.9385 705.1185 928.29

g6 933.5386 282.0686 760.09

4f6 (7F 4 )6p

SPECTRUM AND ENERGY LEVELS OF Eu I I I

TABLE I. (continued)

Configuration Designation J Level (cm-') Configuration Designation J Level (cm-')

32 86 944.83 34 88 753.4524 87 820.98 4fJ(7Fa)6p (6,11)0 712 87 710.15

4f'F(75)6p (5,14)0 62 87 041.33 61 89 178.5352 87 959.80 44 89 639.1744 88 166.46 52 90 155.04

Table I contains the energy levels that were found inthe present investigation. We have confirmed the 6Pand 8P terms of 4f6 5d reported in Ref. 2 that werebased only on the interpretation of resonance lines,as well as the level at 39 637 cm-' that has J= 2. Therest of the levels are given here for the first time.Altogether, 104 excited levels of Eu ni are known.For levels that were determined by five or morecombinations, the rms error for their values derivedfrom the least-squares fit is 0.02 cm-'. The Hu17/2 of4f65d is determined by only one line (the only allowedtransition), but it is the strongest unclassified linewithin a reasonable vicinity of its predicted position.The levels 617/2, 6117/2, and 8

P512 of 4fl are also deter-mined each by a single line. The lines are selected fromthe few strong lines in the infrared that are compatiblewith the rest of the identified multiplets of theseterms. These arise from 4f7 6P-4f6 (7F)5d 6D and4f7 6I1-4f 6 Q(F)5d IH transitions. The lines that wouldconfirm them are too far in the infrared for photographicobservations.

In Fig. 1, the energy levels of 4f 6 (7F)5d and 4f 6 (7F)6sare plotted vs J. Levels of the latter configuration aredistinguished by heavier horizontal lines. Those of4f8 5d that have not been found are given as dashedlines at their calculated positions.

Levels of 4f5 (7F)6p are shown in Fig. 2 with connectedgroupings in Jj] coupling.

CALCULATIONS

The complete matrices of the 4f 6nl configurations areexceedingly large. Considering that only levels basedon the lowest 4ff parent are experimentally determined,it becomes practical to find a suitable truncation of thematrices that provides sufficient accuracy in predictingthe level values, their g factors, and the eigenvectors,and which allows reasonable fitted values of the radialintegrals to be obtained. This is a large task; our solu-tion is not completely satisfactory for all of our observedconfigurations.

The simplest approximation is to assume that the4f6 (7F)nl may be taken as an isolated subconfigurationthat is unaffected by levels based on higher core terms.In this model, the 7 F core should be exactly reproduciblewith the truncated spin-orbit matrices. As mentioned,examination of the experimental levels of 4ff 7F

obtained from triply ionized europium in solution8

shows that this approximation would lead to calculationerrors of -200 cm-', because of deviations from theLand6 interval rule.

The next-simplest approach is to build the distortionsof the 7F core term into the truncated energy matrix.In Jj] coupling, the diagonal spin-orbit matrix ele-ments for the core are the energies of the 7F core levels.Thus, we constructed these matrices for each J with theappropriate core level values taken from Ref. 8 (TableII) and transformed them to the LS scheme in which the

52

50-

48F

E000

(/)-J

>

-J

0zId

461

44)-

42-

401-

_/_/ -/ G_

- -, -

- 4f'('F)sd,6s

'I-, Eurm

/

36[-

34

V I2 2"12 31/2 41/2 J 5''z 61/2 7 1'2 8'12

FIG. 1. Energy levels of 4f'('F)5d and 4f6(7fl6s subconfigura-tions of Eu ii. The levels of 4f6 6s are drawn as heavier horizontallines. Unknown levels are given as dashed lines at their calculatedpositions.

electrostatic interactions were calculated. For the4f6 (7F)6p subconfiguration, this approximation provedto be excellent, insofar as level positions and parametervalues are concerned.

Five parameters were used to calculate 4f6(7 F)6p: aconstant A for all levels, which multiplies a unit matrix,the Slater parameters F2 , G2, and G4, and the spin-orbit

November 1974 1487

J. SUGAR AND N. SPECTOR

92-

90-

881

E000

0)-JW

-J

0

wUJ

zw

86

84

82

80 -

78

\

__ -\ (6,3'2)- (5,2/2)

(4

,3/2)

( - -37"2

- \(O,72) - (2,3'2)

\,7O1,'/2)

-- (4,'/2)

--- (3,,'2)

- -(2,'/2)--- (I ,'2)

(0,'2)

"(6,'2)

-- (5,'"2)

4f6 ('F)6pEum

I I I I I I I 1'/2 1I"2 2"z2 3"z 41/2 5"12 6"z2 7',2

FIG. 2. Energy levels of 4f6 (F)6p subconfiguration of Eu II.Levels are grouped according to Jij coupling. Unknowni levelsare drawn as dashed lines at their calculated positions.

parameter Pp for the 6p electron. Values for theseparameters were adjusted by least squares to fit the34 known levels of this subgroup of 36. The resultingparameter values and their standard errors are given inTable II. An excellent calculation of level positions

TABLE II. Fitted values of the energy parameters for the4f6 (IF) 6p configuration of Eu III.

Parameter Value (cm-') Std. error

A 83 093 i 12F2 5664 4120G2 1586 ± 57G4 1693 4 82rp 2925 A 11

rms error of calculated levels= 36 cm-1

with an rms error of 36 cm-' was obtained, showing thatexcept for the distortion of the 7F core there is noimportant mixing with levels based on higher corestates. The electrostatic parameters are 6-12% smallerthan the relatively constant values reported for otherdoubly ionized lanthanides, but the value for D, fallsexactly on the curve in Fig. 1 of Ref. 6 that shows itsvariation across the 4f period. The results of the calcula-

tion of 4f6 (7F)6p are given in Table III, including acomparison of the calculated and observed levelpositions and the two largest components of theeigenvector for each level in the Jij coupling scheme.

The same truncation of the configurations 4f6 5d and4f 66s was attempted. After adjustment of the parametervalues, the calculated levels were found to fit all of theexperimental levels reasonably well, except tf e 6P and8P terms of 4f6 (7 F)5d. These terms deviated from theircalculated positions by -500 cm-'; 8P was 'too high and6P too low. The fit to these terms was not improved by

TABLE III. Calculated energy levels and percent compositionin Jij coupling of the 4f6('F)6p configuration. Only the first twocomponents of the eigenvectors are given. Units for levels are cm-'.

J Calc. levels Obs. levels Calc.-Obs. Composition (%o)

04 78 988

79 75384 55086 194

11 79 426

80 30483 04784 505

85 11186 935

24 80 13481 080

83 82384 90685 943

87 834

31 81 04981 972

84 68085 671

86 97288 770

41 82 09382 92885 508

86 72488 19489 648

51 82 23483 90986 295

87 912

90 135

64 84 453

87 043

89114

74 87 705

78 982

79 63984 563

79 43780 253

83 00984510

86 933

80 153

81 06783 777

84 93885 928

87 821

81 05981 985

84 640

85 70586 94588 753

82 102

82 95585 480

86 76088 166

89 639

83 24883 960

86 28287 960

90 155

84 487

87 041

89 178

87 710

6

114

-13

-115138

-5

2

-191346

-32

1513

-10-13

40

-34

2717

- 9

-27

28-36

289

-14

-5113

-48

-20

-34

2

-64

- 5

(042)

(1,4)

(1,11)

(2,14)

(1,1)(2,1)(1,11)

(0,14)

(2,11)(3,14)

(2,4)

(3,4)(1,11)(2,12)

(3,14)(4,11)

(3,4)(4,4)(2,14)(3,11)

(4,14)

(5,14)

(4,4)(5,4)(3,14)(4,14)(5,14)

(6,14)

(5,4)(6,42)(4,14)(5,14)

(6,14)

(6,4)

(5,14)(6,14)

(6,14)

(1,2) 27(0,4) 28

(2,14) 32(1,14) 30

(2,4) 15(1,4) 16(0,14) 40(1,14) 38

(3,14) 21

(2,1D) 23

(3,2) 9

(2,1) 10(2,14) 31(1,14) 38

(4,14) 23(3,14) 25

(4,4) 6

(3,4) 6(3,14) 12(2,14) 14

(5,14) 29

(4,14) 30

(3,14) 5(5,14) 4

(4,4) 3(4,1) 3

(6,14) 39(5,14) 38

(4,14) 6

(6,14) 6(5,4) 5

(5,1) 1(6,4) 5

(5,14) 5

(6,4) 5

69726867

80

8344

5461

72

85875552

60

71

87897975

5867

89

90

919053

59

9191

93

97

92

95

95

100

100

V~ol. 641488

SPECTRUM AND ENERGY LEVELS OF Eu i 1 I

TABLE IV. Fitted values of the energy parameters for the interact-ing configurations 4f0 (QF)5d and 4f6 Q(F)6s of Eu iII.

Parameter Value (cm-') Std. error

A (Sd)A (6s)E1(f6)5d,6sE'(f8 )E3 (f6)

F2(fd)F4 (fd)G'(fd)G3 (fd)G'(fd)G'(fs)-f (fd)f (fs)

rd(fd)D'(fd)D5(fd)X2 (fd)X 4 (fd)

46 33950 803

586327.5

55822.5

19 12912 270

778177037023221911811170898

-20430

-3975-2667

41 254 53fixedfixedfixedfixedI 2404± 480A 1204 5204± 2804 1404 124 164 304 230fixed

A 4804 640

Configuration interactionR

2(fd, fs) 0 fixed

RI(fd, sf) -5519 d2000rms error of calculated levels=95 cm-1

addition of the effective electrostatic operators thattake into account far-configuration interaction.

This led us to try the next order of complication,addition of the next-lowest core term, 'D. In doing so,we had to abandon the use of the real 7F core levels andlet the core spin-orbit interaction parameter tf deter-mine the core-term splitting. With the introduction ofhigher levels of 4f15d through 4f6 (5D) (actually weadded the three 'D terins distinguished by seniority)we obtain a dramatic improvement in the calculation.The fit of the 8P and 6P is now about as good as therest of the levels, except for the 8P5 / 2*

There is, however, a problem concerning the values ofsome of the fitted parameters. The three 'D core termswere added to both the 4f'5d and 4f66s configurations,because we wanted to add configuration interactionbetween them. For both configurations, a fitted valueof Pf of -1175 cm-' was obtained. In Ref. 8, a value of1326 cm-l is derived for rf from the observed levels of4f6 in Eu3 +. Therefore, we have obtained an effectivevalue that absorbs the effect of higher core states. This

TABLE V. Calculated energy levels and percent composition in LS coupling of the 4f6 (7 F)Sd and 4f6 ('F)6s configurations withinteraction. Only the first two components of the eigenvectors are given. Units for levels are cm-'.

Config-Calc. Obs. Calc. uration

J levels levels -Obs. 4f6(7F)nl

04 38 13538 47745 89446 19546 93948 297

13 33 97135 73738 35638 9513931545 83346 55047 64148 79149 158

22 34 45136 94938 82439 51739 61140 98843 53746 09047 13648 44249 56249 891

34 35 11238 12339 52340 3214072042 59043 99346 683

38 050

46 096

48259

33 85635 62738 31739 014

46 519

48 829

34 394

38 82839 76939 63740 89843 39646 10947 17348 49649 61149 906

35 10938 22939 58040 3724087142 53143 88546 793

85 5d5d5d

99 6s5d

38 6s

115 5d110 5d39 5d63 5d

5d5d

31 6s5d

38 6s5d

57 5d5d

4 5d-252 5d-26 5d

90 5d141 5d

-19 5d-37 6s-54 5d-49 6s- 15 5d

3 5d-106 5d-57 5d-51 5d-151 5d

59 5d108 5d

-110 5d

Composition (%)8

G

8F6

D8

F6

F6

F

8 H8D8

G8

F

6F

8F

8G

6D6F

6G

8H8D

8G

8P

8F

8p

6H

6F

8F

6D

6F

6G

8H8D

8G

8F

8p

6p

6H

6F

656554925593975661

61554794498778

977461395245955494547858

9790635969649559

8F27

8G28IF 33(

6D1)ID 2

ID 355d IF 2

(5D1)G6 26p 38'F 308G 33"D 41ID 39(5D1)6D 20F 35

5d 6G 86F 10

(5D1) 6 G 16p 19

8F 296p 238G 20OP 39(5D1) 4G 2ID 316F 20F 215d 6G 156s 0 F 18

(6D1)6G 16P 40F 298G 336P 258p 270G 2ID 25

Config-Calc. Obs. Calc. uration

J levels levels -Obs. 4f0 (QF)nl

32 47 9224927950 48250 756

42 35 94139 17640 4274116242 22844 57647 60348 86350 06651 26751 820

54 36 92240 20241 48942 06145 27249 18249 91451 76053 025

62 38 03642 64643 00946 05351 01952 096

74 39 26643 81746 889

82 40 604

47 99449 2925042650 806

35 97239 226405184115942 08444 55447 71548 92549957

51 848

36 96240 13341 57341 98845 31449 08649 92651 65152 960

38 06742 65842 85046 15150 96552 100

39 29043 65947 070

40 659

- 72- 13

56- 50

- 31- 50- 91

314422

-112- 62

109

- 28

- 4069

- 8473

- 4296

- 12109

65

- 31- 12

159- 98

54- 4

- 23158

-181

- 55

6s5d5d6s

5d5d5d5d5d5d5d6s5d5d6s

5d5d5d5dSd5d6s5d6s

5d5d5d5d6s5d

5d5d5d

5d

Composition (%)

8F

6D

6G6F

8H

8D

8G

8F

8p

6H6F

8F

6D

6G

6F

8H

8D8G

8F

6HJ-

6F

8F

6G

6F

8H

8G8F

6H

8F

6G

8H

8G6H

8H

95573754

9895676697946496635991

999772719581988097

997980949895

999392

100

6F 2

6G 246s 6F 425d 6G 27

(0

D1)6G 1IF 3OF 280G 30

6D 26G 36D 210F 2

6G 23OF 215d

0G 4

6H 16F 10

F 258G 266G 36G 155d OF 10F 15

8F 1

6H 1OF 17

8G 178G 35d 6G 18F 2

6H 16H 78G 7

November 1974 1489

J. SUGAR AND N. SPECTOR

probably also accounts for the value of D', one of theeffective electrostatic operators, which is three times aslarge as is found in Tm iii,6 for example.

Since the spin-orbit matrices are the same in 4f 66pand 4f6 5d, and since the direct electrostatic interactionis diagonal in the core-state spin, we conclude that theexchange interaction in 4f65d is responsible for themixing in of higher states that perturb the positions ofthe low levels. The exchange is small in 4f 66s and4f 66p and does not cause the same problem there. It didnot appear fruitful to pursue a more-complete calcula-tion, because no levels based on higher core terms areknown and, from a practical point of view, the size ofthe matrices grows very rapidly with the addition ofmore core terms, making computer space and time aconsideration.

Significant configuration interaction between 4f 65dand 4f 66s occurs in the J= 5 and J= ' levels, where the5d 6G and 6s 6F terms cross (see Fig. 1). We addedconfiguration-interaction matrix elements and, of thetwo radial integrals, were able to derive a meaningfulvalue for only R3 (fd,sf). The error in R2(fdfs) exceededits fitted value so we eliminated this parameter fromthe calculation.

The final set of parameter values derived in the least-squares fit is given in Table IV. The core parametersEk and a for both 4f 65d and 4f 66s were fixed at valueslinearly interpolated between Pr m9 and Tm iii.6 Theeffective electrostatic operators Dk and Xk are scalarproducts of unit operators as defined by Goldschmidt'0

and used by Sugar and Kaufman." As in Refs. 6 and 11,D3 was undefined by the least-squares fit and wasdropped.

The calculated energy levels and composition in LScoupling are given in Table V. The three 'D parentstates are distinguished by numbers, as given byNielson and Koster.'2 Where the second-largest compo-nent of the composition is contributed by a differentconfiguration the term is preceded by the outer electron(either 5d or 6s).

It is tempting to improve the level fit for the J= 2

group by interchanging the levels 39 769 cm-' and39 637 cm-'. However, they must be assigned as givenbecause the level at 39 769 cm-' contains a much higherpercentage of 'P and consequently there is a very strongtransition to the 8S ground level. The observed Zeemandata of Ref. 1 (as interpreted in Ref. 2) for the resonancelines is compared in Table VI with the calculated gfactors. They confirm our level assignment. Comparedwith the results of Ref. 2, our calculation makes nlomarked improvement of the g factors, although we havethe advantage of knowing many more energy levels.There is a better correlation between the percentage of

TABLE VI. Observed and calculated g factors for levels of 4f65dcombining with the 'S 7 /2 ground level.

Resonance lines Calc.Obs. level J sObs. g Calc. g X (A) Int. %

8P

39 636.88 24 1.592 1.718 2522.143 200 1439 769.05 24 2.025 1.946 2513.759 2000 3940 897.66 21 2.027 2.080 2444.382 1000 4540 870.60 31 1.885 1.860 2445.992 4000 6942 530.91 31 1.860 1.774 2350.514 200 2742 084.25 44 1.762 1.772 2375.460 4000 97

See Ref. 2.

8P in Ref. 2 and our observed intensities, especiallyfor the level at 39 769 cm-'. We think this is becausebetter values for the parameters were obtained byinterpolation than by fitting to the observed levels,although we have a better energy fit. The calculationwill undoubtedly be improved by a less-severe trunca-tion of the energy matrices, but it must improve thecorrelations in Table VI to be meaningful.

IONIZATION ENERGY

A value for the ionization energy of Eu iII was derivedby Sugar and Reader'3 from the 4f6ns series, usinginterpolated values for the positions of series termsrelative to the ground level. The accuracy of thecalculation may now be greatly improved by insertingthe experimental value for the lowest level of the 4f6 6sconfiguration. There remain the uncertainties that arisefrom the interpolated value for the energy intervalbetween 4f 66s and 4f6 7s and from the assumed valuefor the change of the effective quantum number An*between them. Taking the error estimates from Ref. 13,we obtain the value 201 000= 800 cm-' (24.92ht0.10eV) for the ionization energy.

REFERENCES

'H. N. Russell, W. Albertson, and D. N. Davis, Phys. Rev. 60,641 (1941).

2W. C. Martin and J. Sugar, Astrophys. J. 184, 671 (1973).3S. N. Bodrug, E. G. Valyashko, V. N. Mednikova, D. T.

Sviridov, and R. K. Sviridov, Opt. Spektrosk. 34, 312 (1973)[Opt. Spectrosc. 34, 176 (1973)].

4C. K. Jorgensen, Prog. Inorg. Chem. 4, 73 (1962).5H. A. Weakliem, C. H. Anderson, and E. S. Sabisky, Phys.

Rev. B 2, 4354 (1970).6J. Sugar, J. Opt. Soc. Am. 60, 454 (1970). An unpublished

calculation of 4f"5d, including the effective operators Dk andXk resulted in the values D'= -710, D' (undefined),XI= -2340 and XI= -2630 cm-'.

7A. Carlier, Contribution d 1'.8tude Theorique des Spectres d'Arcet d'Etincelle du Samarimn (Ph.D. thesis, Facult6 des Sciencesd'Orsay, 1967).

8W. F. Carnall, P. R. Fields, and K. Rajnak, J. Chem. Phys.49, 4450 (1968).

9S. Feneuille and N. Pelletier-Allard, Physica 40, 347 (1968)."Z. B. Goldschmidt, J. Phys. B 3, L141 (1970)."J. Sugar and V. Kaufman, J. Opt. Soc. Am. 62, 562 (1972)."C. W. Nielson and G. F. Koster, Spectroscopic Coefficientsfor

thte pn, dn, and fn Configurations. (M.I.T. Press, Cambridge,Mass., 1963).

"J. Sugar and J. Reader, J. Chem. Phys. 59, 2083 (1973).

1490 Vol. 64

November 1974 SPECTRUM AND ENERGY LEVELS OF

APPENDIX. Spectral lines of Eu HII

Eu II I 1491

Wavelength InesiyWavenumber Clsiicto Wavelength IntensityI Wavenumber Casfcto(A) Inesiy (cm-') Clsiiain(A) ~ 'j (cm-,) assias

2026.9312038.2722041.2442060.4462064.5812073.3952090.2172093.1072093.5042103.0732113. 1432124.6942136.0662153.5912153.9602157.8222159.8032161.2852167. 1192170.0672171.0032173.592,2174.5602175.5672182.5252184.6772184.9722190.5882193.2142194.8062196. 1732200.0212201.2362206.739

2207.9012209.8622211.6032211.8462212.3422212.6342214.5402214.66422 15.3442217.2272217.8962218. 1882219. 1922219.3312219.4202220.0182223. 1272224.0812224. 1742228.4602230.6292230.7022231. 1432231.3132234.7322235. 1682236.3212240.1412241.4202243.0792244. 7492244.7962250.8512252.4122255.598

11252

10121011

30124684

1022

10271

102105102354

813

202

203

201030373

3020

41032312232

103

101313341

49319.7849045.4148974.0248517.6648420.5148214.7147826.7247760.6847751.6447534.3847307.9047050.7446800.2846419.4746411.5246328.4646285.9746254.2346129.7446067.0846047.2245992.3745971.9045950.6345804.1545759.0445752.8545635.5745580.9345547.8845519.5345439.9345414.8545301.61

45277.7645237.6045201.9745197.0345186.8845180.9345142.0345139.5245125.6645087.3345073.7445067.8145047.4245044.6045042.7945030.6744967.7044948.4144946.5344860.1044816.4844815.0144806.1544802.7444734.2044725.4844702.4244626.2044600.7344567.7544534.5944533.6644413.8844383.1044320.41

36962 11,2-862821,240133 11,2-8917813,23806713,2-8704113/12

36962 1112-854799/239289 1112-87710 i1/2

3806711/2-86282711/2

401331112-87959-11/2

392891512-87041-13/2

392259,2 -86760-9/2396365,2 -86944-7/24065917/2 -87710-15/2

411599,2 -87959~1,12

3806713/2 -84483613/2382297,2' -846407124285013/2 -89178-73/23696211/2-832487,1/2392259,2 -85479912359721,2 -82101-9/2

408971,2 -869447/123696211/2-829549,2419871112-87959-1112

351087,2 -81059-7/2

343945/2 -80153'S/2

425307,2 -881669/233856 3/2 -7943737/2382297,2 -837765/24365915/2 -8917873/32356273,2 -81067.7/2392259,2 -846407/2396365,2 -849385/24265811/2 -879597,1/2

39289151,2-84486713/2415731112 -86760912380671312 -832487111

3696211/2 -8210179/233856 3/2 - 78981 112

35972912 -81059712

35 10811343945/2

4089711

-801537,2,- 7943737/2

-85928.7/2

388281,2 -837767,12

42850 1:1,2 -87710 75,2

392251/2 -839597,1,2

35627:1/2 -802537/32

42530712 -869447,242658 I:12 -87041 13/2

411591,2 -854797/32

225.9382261.8812262.1912262.5482264.9372265.7362267.4632269.3862269.4532271.2662271.4082276.8522281.0022282.6572284.4872287.0792291.6162291.8092299.3052304.3742311.9212314.9172316.9262316.9932317.9772327.6882331.0122331.1452331.4112332.8282332.8602333.8422334.3382334.3872334.5622334.8192334.8772335.1142335.6592336.3912336.9572337.4432337.5272337.5922337.8282337.9512338.4322338.5352339.8422340.2932340.4802340.8372341.4372342.3442342.4532342.9662343.0972343.4732344. 1632346. 1202346.8302347.6352348.5302348.8862350.3822350.5142351.4242351.5672351.8282351.897

310131

204

10S36

208514

403320105312

1032253812

1012321

103313724

10131138S

1012210103210

200

512

44294.1044197.3144191.2644184.2844137.6844122.1344088.5144051.1644049.8644014.7144011.9643906.7343826.8543795.0843760.0043710.4243623.8743620.2043478.0043382.3743240.7743184.8243147.3843146.1343127.8242947.9042886.6742884.2142879.3342853.2842852.6942834.6642825.5642824.6742821.4542816.7542815.6842811.3442801.3442787.9442777.5742768.6842767.1542765.9542761.6442759.3842750.6042748.7042724.8342716.6042713.1842706.6842695.7242679.2142677.2242667.8842665.4842658.6442646.0842610.5242597.6242583.0142566.7942560.3542533.2642530.8742514.4042511.8342507.1042505.86

395797,, -83776s',2

405189,, -846407/52

43659,31 -87710O15,5

35627 = - 796397,1241573,,,-85479;,5,401331ii2- 8 3 9 59 -11s

42658132868'11

436591512 -87041 131

40875,2 -83776-1,2

45313,,,-881069-12

4013311/2 -829549-12

392259,2 -81985,12383163,2 -81067512

453131112 -87959-1,12

40371712 -82954-1,2

07/2 -42530 7/2

J. SUGAR AND N. SPPCTOR

APPENDIX. Spectral lines of Euml-Continued

Wavelength 1nen1t Wavenumber Clssfiato Wavelength Inen1t Wavenumber Clsiicto(A) JItniyj (cm-') J lsiiain(A) Itntyj (cm-') J Casfcto

2352.2842352.9612354.8832357.8742358.2672359.0802360.6512360.8502361.3972362.2392362.8202363.7582364.5872366.5222366.9412367.4092368.0432368.5912370.0672370.8142371.0712372.5882373.5532373.8872374.0852374.2102375.2032375.4602376.4232376.4782377.2332377.7892377.8622378.9172379.4962380.4822380.6892380.9282381.5272381.6522381 .8132382.0712382.4932383.5322383.6182383.8072384.1182384.2152384.519

2385. 1612385.5732387.2942387.3842387.4562387.6272387.9752388.9662389. 1072389.5122389.9832390.4802390.7732391. 1072391.5862391.8972392.5932394.6582395.5392395.617

I1013

107

10101213

201323

204351223

20I

104000

102

208S2322522

10585

1042

5

31

2022141

20

1034

205

2010101

20

42498.8642486.6542451.9642398.1242391.0542376.4542348.2542344.6842334.8742319.7842309.3842292.5942277.7642243.1942235.7342227.3842216.0742206.3042180.0142166.7242162.1642135.2042118.0842112.1442108.6442106.4142088.8242084.2642067.2142066.2442052.8842043.0542041.7642023.1242012.8941995.4841991.8341987.6241977.0641974.8641972.0241967.4741960.0541941.7641940.2541936.9241931.4441929.7441924.40

41913.1141905.8841875.6741874.0941872.8341869.8241863.7241846.3541843.8941836.7941828.5641819.8641814.7341808.8941800.5241795.08-41782.9341746.8941-731.5541730.18

44553 9/2 - 86944'712

396365,2 -81985-7,2

433955,2 -857057-12

39769112 -81985,72445535,2 -86760:912

470691512 -89178%,12

41159112 -83248?,,1207/2 -420849,2

390141,2 -81067,1243885 7/2 -85928,12

41987 ,l,2-839591I,2

467937,2 -88753712

383163,2 -80253312

382297,2 -80153,~$2477141,2 -896391/2

420849,2 -839597',12

383161,2 -80153,12426581.1,2 -8448613,2438857,2 -857051-,2

411591,2 -82954-9/2

403717/2 -82101912

2395.8312395.8632395.9072396.0442396.6582397.5992397.7802397.8622398.7882398.9312400.9512401.0022402.0522402.3372402.6992403.7392404.0752404.38524,04.9942406.1422406.2902407.3012408. 1252408.3182409.2032409.6262410.0792410.8422410.9262411.5112412.0242412.4082412.5482412.9552413.2652413.4082413.4462413.6242415.4852416.2962417.8992418.0852418.2792419. 1142419.2462419.5782420.4352420.4,69

2420.6762420.7302421.9502422.0022422.8962424. 1372425.3322425.5372425.6792426.7332427.6662428.2842428.8342429.3182429.6602430.0382430.9112431. 1342431.491

2431.765

1232S2S32052

204

20.33

202

10

202203

102051

40

320201025I2I

210101025

2

43010510I50S402

40

101S10

10

41726.4741725.9041725. 1541722.7541712.0641695.7041692.5541691. 1241675.0341672.5441637.4841636.6141618.4141613.4641607.2041589. 1941583.3841578.0241567.4941547.6741545.1241527.6741513.4541510. 1341494.8841487.6041479.8041466.6841465.2341455.1641446.3541439.7641437.3541430.3741425.0541422.5841421.9441418.8841386.9841373.0841345.6641342.4741339.1741324.8941322.6341316.9741302.3441301.76

41298.2341297.3041276.5141275.6241260.4041239.2641218.9641215.4641213.0641195.1641179.3241168.8441159.5241151.3341145.5441139.1341124.3641120.5941114.55

41109.91

38050112 -79437,12

467937,2 -88166-,2

388281,2 -80153',,238316:1,2 - 79639 ',2

42658,:, - 359,46519312 -87820.'5/2

39769s,2 -81067,5i

41987,11/2-83248',1,2390143,2 -80253-3,2

011,2 -411599,2445531,2 -85705-1,2

390143,2 -80153-512

383 16:1,2 - 79437,3/408707,2 -81985712433951,2 -845103,1428501:112- 83959 71,2

1492 Vol. 64

4157311,2 -8324871,2

428501112 -844863,12

40371712 -81985,-2

380501,2 -79639-1 /

405189,2 -82 101 9,1

395797/2

39579 7/2

40518 912

-81067,2M-810597/2-81985 7/2

453131,,2-86760:12

39636,,2388285,,396365,2

-81067,',-802531.,',- 81059 7'1

November 1974 SPECTRUM AND ENERGY LEVELS OF Eu I I I

APPENDIX. Spectral lines of Eu mtt-Continued

Intensngh ty avenmbe IIWavelength I WavenumberWavelenth Intensity W cnnmClassification (A) Intensity (cm') Cl_ ion(A (c -' (A- Cm,

2432.5492433.2382433.6472433.9262434.1922435.1352435.9812436.3942436.6422436.7722437.2372438.7402438.8292440.1692440.2622440.6692441.6312441.7102442.3452442.4162442.6522443.0872443.2182444.3822444.8112445.2332445.9922446.1792446.4342447.0412447.3132447.5592448.0732448.5662448.6932448.7522449.3012450. 1102451.2372451.7292452.2452453.4462454.7262455.0862455.2152455.8922458.3502459.8662461.7862462.9032463.3012463.8962464.3752464.4712464.8562465.1592465.8872465.9812466.7172469.3312469.5312470.1982470.5122471.3352471.7642474.5262474.9392476.2382476.4472477.775

10I

103

10lOObi

6205.

1035

102

10502b34245I

10008I

40004

30b42bl81

203621

20102125

30553

105

3072

3012241527

40238

10102010

41096.6841085.0341078.1441073.4241068.9441053.0441038.7841031.8241027.6541025.4641017.6340992.3540990.8540968.3440966.7940959.9540943.8240942.5040931.8540930.6740926.7140919.4340917.2340897.7440890.5740883.5140870.8340867.7040863.4440853.3040848.7740844.6640836.0940827.8740825.7540824.7740815.6140802.1340783.3740775.1940766.6140746.6740725.4240719.4440717.3040706.0840665.3840640.3240608.6340590.2140583.6640573.8640565.9640564.3940558.0540553.0740541.1040539.5540527.4740484.5640481.2840470.3440465.2040451.7440444.7140399.5740392.8440371.6540368.2440346.61

1493

4908611,-901551112438851712 - 849385,247714,2, -88753°712

467937,2 -87820°s,2

4531311(2-86282,X1241987,1,2 -82954912

38050,,, -78981 112

073- -408975,246150,382-87041 1312

071,2 -408707,2

461085,2 -86944 71243659 1,52 - 8446 61312

461085,2 -869333,2

470691512 -87710 752,388285,2 -794373-,

39579712 -801535-,2

49086 ,,,2 -89639,°,240518,,2 -81059,7,2

39769,12 -802531,2

477149,, -88166912

07°/2 -40371712

492927,2 -896397,,

2477.9882479.7122480.0182480.6242482.2322482.9992483.2882483.3862484.7352486.9192487.0192487.9942488.9072490.4952491.0792492.1482492.4262492.4812492.8782493.8362494.0332495.1482496.9232498.4022499.1712500.3312500.3872501.0312501.9122502.9672503.3942505.4552505.5072507.6462509.1202511.4742512.9532513.7592517.9402518.5532519.2482519.5962519.9962521.3462522.1432523.4462525.3002526.1422526.4712528.9022529.5292537.5102538.9812539.1382548.3012548.5862549.4222550.9212553.9932554.5012558.0672560.3582560.4742560.5532562.1792562.9932569.1512571.6662571.7512572.342

53

20512

2022

1053

10101025

101332

102

10175125222111

20002052253

20014

,1I1523

10102053c3

10101051155831

40343.1440315.0940310.1140300.2640274.1640261.7240257.0340255.4540233.6040198.2740196.6540180.9040166.1640140.5540131.1540113.9240109.4540108.5740102.1940086.7840083.6240065.7040037.2340013.5340001.2139982.6539981.7539971.4639957.3839940.5539933.7339900.8939900.0639866.0339842.6039805.2739781.8439769.0839703.0639693.4039682.4539676.9739670.6639649.4239636.8939616.4339587.3639574.1639569.0039530.9739521.1739396.8839374.0639371.6139230.0539225.6739212.8139189.7739142.6339134.8439080.2939045.3339043.5639042.3639017.5839005.1938911.7038873.6638872.3638863.44

48496,, -88753:,,

49956,,, -9015571,,,40870F,, -810677,,

45313,,,, -85479n,,

4615013,2-86282-,,,41987 ,,,,-82101 ,,

445539,2 -846072

47069,,,S-870412,,,

42084,,, -81985:,,

4037171, -80153512-0,712 -397695/2

49956,,2 -89639912

07/2 -39636,,,

47714,, -869447,072, -39225,,

504267, -89639;,50965 13n-90155,,,49610,, -88753;,,46793712 -859287,,49086,,,2-88166,,47714,, -86760,,2

46793,7 -85705;7,490861,l2 -87959, ,

J. SUGAR AND N. SPECTOR

APPENDIX. Spectral lines of EumI- Continued

Vol., 64

Wavelength Intesit Wavenuniber 1lsiicto Wavelength Itniy Wavenumber 1 lsiicto(A) ntn~ (cm-,) Casfaio (A) neniy (cm-') j Casfcto

2573.3792574.5912574.6532574.6812574.9072575.6892576.3172576.6602576. 7682584.3872585.3402585.6712590.4602594.7112594.7582596.3382598.8782599.6592599.8322600. 1112600.8772600.9502602.4422603.2862603.6592603.9392604.4422608.3402610.0922613.6962613.7472614.2492616. 1062616.2592616.3272616.3482619.3272619.6062620.0572620.7882623. 1292623.3272623.5692623.6322623.7622624.3682625.0982626.9812627.7642628.4552628.8202629.4292630.5822631.3112631.4142631.4622631.5992631.9792632.4172633. 1802634.3292634.4082634.9092635. 1922635.3362636.3892636.7482636.8702638.6242640.916

1133523S

1212

1020102242422435

103030224c

S0c2010101

4105

20Sc

53S

102c

20c10Sc

5225

1024224c44c35

48

38847.7938829.5038828.5538828.1438824.7238812.9338803.4738798.3138796.6938682.3138668.0638663.1138591.6438528.4138527.7238504.2738466.6538455.1038452.5338448.4038437.0838436.0038413.9738401.5238396.0138391.8938384.4738327.1238301.3838248.5838247.8438240.4838213.3438211.1138210.1238209.8238166.3538162.2938155.7238145.0738111.0438108.1638104.6538103.7438101.8538093.0538082.4538055.1638043.8338033.8238028.5338019.7338003.0737992.5337991.0537990.3637988.3937982.9037976.5737965.5737949.0237947.8837940.6737936.6037934.5237919.3737914.2037912.4537887.2537854.37

499055,2 -88753',,2

o;7,2 -388285,12

499569,2 -887537-12

492927,2 -878205-12

46096112 - 84563 '12

484961,2 -869447;12484965,2 -8693333,2

460961,2 -M4103,2461085,2 -845103'/2

504267,2 -88753-7,2

499251112 -88166912509651112 -89178'2,,2

496105,/2 -87820O112499569,2 -88166912

467937,2 -84938-5/2

488281,2 -869333-12

52099 ,:1,2 - 90155 -Il2465193,2 -84563-1/2499251, -7959 '

489251,2 -86944-7,2499561,2 -879591,2

465192,2 -845103-12477141,2 -85705-7,2516501112 -896399-12

50805V72 -88753712

47931 -85928-5/2

2642.2722643.3222644.2822645.2182645.3452646.4162647.1622648.3832649.5282650.7412650.9312653. 1942653.5632653.9352654.3222655.0922656.8192656.9092657.0322657.8762658.7322659.3122659.8792661.7362662.2412662.6882665.2082665.2692666.8582667.6772668.2072670.7272671.6802671.7982672.0542672. 1782672.3472673.2722673.3762674.4442676.0862676.2702677.3392677.4162678.1232678.5382680.3682681.0212682. 1652683.0222683.2142683.6332683.8382683.9142684.8402685.7682685.8202685.8762686.1272686.1872686.4292687.2412687.7392688.4692689.6792691. 1102691.6432692.8632693.5072693.626

1494

30c31

20Sc

Sc

41

20c10123

10117141I5

10112h

20c2

20c13c832222h4h

40c2h222h422c2cIC

20c212

1

23

20535h

20c3/i5c5Shc4

40c2

37834.9537819.9137806.1937792.8137791.0037775.7137765.0637747.6437731.3437714.0737711.3737679.2137673.9637668.6837663.1937652.2737627.8037626.5337624.7837612.8437600.7337592.5237584.5137558.2937551.1837544.8637509.3637508.5137486.1737474.6637467.2137431.8637418.5137416.8637413.2737411.5337409.1737396.2337394.7737379.8337356.9037354.3437339.4237338.3537328.4937322.7237297.2337288.1437272.2437260.3337257.6737251.8537249.0137247.9537235.1137222.2437221.5237220.7437217.2737216.4437213.0937201.8437194.9537184.8437168. 1237148.3637141.0037124.1837115.3037113.66

489259,2 -86760,92

5I1842, -896399'/2

471731,2 -849385-1

47993712 -857057-12

490861112 -86760912

4929927,2 -86944?,12

47993712 -854799-12

471735,2 -84640,72444965,2 -859285-12

47069, 1 -84486132,

48925112 -86282',,12

49610112 -86933-312

46519112 -83776-312

SPECTRUM AND ENERGY LEVELS OF

APPENDIX. Spectral lines of Eu iii-Continued

avength Intensity Wavenumber Classification Wavelength Int ty Wavenumber Classification(A) It y (cm-, ) (A) ntensi (cm-')

2694.3952694.8012695.2882695.6022696.0472696.1732696.5632696.8582697.2042697.4652697.6202697.8942698.1942699.8692700.7812701.6702702.1142703.9232703.9962705.5002705.6582707.6122708.1852708.2542708.8402709.8002709.8862710.8222712.0842714.79227 15. 1872715.3962716.5122716.6642716.8142717.4682718.8552719.0952719.2612719.7112720.6682721.2022721.3162721.4292723.5112724.8492725.1672725.5422726.3302727.5562727.9452731.1552731.3762731.6242733.6852736.0422737.5292738.4912738.5792739.6512739.9542743.5782743.9432747.2672747.8642749.7522751.4482752.6242752.6822753.322

2h10Sh4c14822h1225

2020c222c42112

lOc2 0c42h2h

1023422S42323

SOcSc8b424h2h

20c12hSh4c32h4SblS327c25h

103h52h25h

102

37103.0737097.4937090.7737086.4637080.3337078.6137073.2437069.1837064.4337060.8537058.7237054.9637050.8437027.8437015.3537003.1636997.0836972.3436971.3336950.7836948.6336921.9736914.1536913.2136905.2236892.1536890.9936878.2536861.0936824.3236818.9636816.1336801.0136798.9436796.9236788.0736769.2936766.0436763.8036757.7336744.7936737.5836736.0436734.5236706.4436688.4136684.1336679.0936668.4836652.0036646.7836603.7136600.7536597.4336569.8436538.3436518.4936505.6636504.4936490.2036486.1736437.9736433.1236389.0436381.1436356.1736333.7636318.2436317.4636309.03

46150 13/2 -8324811/2

52099 1312-891781,32

499055,2 -86933/31250805 7/2 -87820 °,2

46096112 -830093132518481,2 -887537-,,

45313, 1,2-821019-12

433955/2 -80153'i,25096511/2 -87710 5,2

5296011,2 -89639 ,/2

479937/2 -846407/2471735,2 -83776is/2

50426 7/2 -86944 7°244553 ,,2 -81059-,,2

46519 312 -83009°32

49925,, 2 -862821 12504267,2 -86760 °2518489/2 -881669,3496105/2 -859285'/251650,1/2 -87959', 2

48259 1/2 -84563 12

48259 1/2 -845103/2

52960 112 -89178 13/2

2753.7422754.6702755.1242757.7492757.9352760.2082760.6572761.7242763.5842766.2572768.3752768,5422769.7062770.7872771.0562773.0142775.2142780.4752781.6732785.2412791.3482791.4932792.0602792.5142793.0182793.9952795.5362797.5122797.6072803.9922806.1082807.5892807.9332808.0912808.3532808.5072808.8572809.0002811.9922814.1412816.8982817.5782819.2512821.7802823.2162823.9752824.8942825.7822825.8992829.7422831.4562832.1062832.5452833.2292833.462 -2836.3292839.5572842.7482842.8042844.9872846.3232848.4362848.5512850.1392850.3942854.2612858.9992860.6192862.5602864.525

33

20104

20c2

104

lOc20clOc10333c3

20c13112

20351212513

102552733

1033335221312lc15

20c53

205

lOc55

20553lc2

36303.4836291.2736285.2836250.7536248.3036218.4636212.5636198.5836174.2136139.2536111.6136109.4336094.2636080.1736076.6736051.1936022.6335954.4735938.9835892.9435814.4335812.5735805.3035799.4635793.0135780.4935760.7735735.5135734.3035652.9335626.0435607.2635602.8935600.8935597.5835595.6235591.1935589.3735551.5135524.3635489.5935481.0335459.9735428.1935410.1835400.6535389.1535378.0235376.5535328.5235307.1335299.0335293.5635285.0435282.1335246.4835206.4135166.8935166.1935139.2235122.7235096.6735095.2535075.7035072.5635025.0534967.0034947.2134923.5134899.55

508057,2518489,2488283,2496105,2

-86944°7/2-8795911/2-849385/2-85705712

499055/2 -85928 5/2508057/2 -867609°/2

49905112 -857057/2

4908611,2 -84486 ,3{2

5296011/2 -88166912

50805 7/2 -85928-5/2S184819 2 -86944,°72

50805 7/2 -85705?,,2

November 1974 Eu i I I 1495

Vol. 64J. SUGAR AND N. SPECTOR

APPENDIX. Spectral lines of Eu III- Continued

Wavelength Intensity Wavenumber Classification Wavelength n Wavenumber classification(A) (cm-') (A) 'n (cm-,)

2871.0042871.8982871.9732874.9132883.1312889.8542892.6022896.6872903.2632911.5202911.6432912.2262912.6402913.0372915.1652916.8172917.1152920.4932921.0092921.5602924.2122927.8502928.9102930.9952933.3102940.0272940.3092944.0372946.1882947.7372949.5552950.1952951.7332956.3472956.7442956.9022958.1792972.2952976.5412982.2932992.0302998.4503000.1133000.5003006.3673011.5483012.6753013.2833015.3313016.4993018.4323018.8063022.0753022.6903023.0973023.2343023.3993023.5843023.9263025.3203026.0943026.2213026.3743026.7923029.6173029.9183030.4833031.2453031.382

3331Sc2

lOc27c12

4040c10533S5S31

1020c

Sc222221

lOc14

20102

lOcS

30c24

20c3

2021

20clc2

lOc

20cSOc3cSc

20c3

lOOc10lOc32c

200c

1S0c

20c5

34820.8134809.9634809.0534773.4634674.3534593.6834560.8234512.0834433.9234336.2734334.8134327.9434323.0634318.3934293.3434273.9234270.4134230.7734224.7234218.2734187.2434144.7634132.4134108.1334081.2134003.3534000.0833957.0433932.2533914.4133893.5133886.1633868.5033815.6433811.1133809.3033794.7133634.2133586.2433521.4733412.3733340.8533322.3633318.0633253.0533195.8433183.4333176.7333154.2033141.3633120.1333116.0533080.2133073.4833069.0333067.5333065.7333063.7133059.9733044.7333036.2833034.8933033.2233028.6732997.8732994.5932988.4432980.1432978.65

49610,, -84510,-,

508051,2 -85479,-s

49925,12-8448613s2504267/2 -849385°251848912 -86282 ,,2

489259,2 -83248 ,X/

46793,,2 -81067°-12477149, -81985712

461085,2 -80253,-,

479937/2 -821019125296011,2-87041 sh/2

471733/2 -81059,°2490861112-82954,12

465193,2 -801535/2

5096513/2 - 84486,312

460961,2 -794373/249925,,12 -83248',2

489259,2 -82101li°12

46519312 - 79639 ,3

47 173512 -80253 ,/479937,, -81067 -12

479937/2 -81059?7/2

489255,, -81985,,2

49925 ,,2-82954°9,249956912 -82954/31250965 3/2 -83959 ,2

471735,2 -801535,12

3032.8393033.5093035.5733036.8033036.9763037.7013038.0693038.5273038.6433039.0533039.8883039.9853043.6463045.3863047.7123048.4403048.6033048.6953049.5853054.0663054.9713059.3733062.2823063.0123063.3553063.7413066.8873069.0993069.9403070.0713070.3953072.8093076.4273079.5743081.6623086.2493086.5333086.7703087.1013087.4913087.9683089.0923090.3833092.7853097.4703098.5513100.9893105.2463108.5793109.6663115.9633119.6273122.5623123.9473124.6863129.1363129.3103132.5813136.7933139.1663139.2873142.5413143.5623144.9933146.0553146.6853147.4263149.1313156.0953156.735

1496

40c545c

20c15c5c

10105

20c3443b3c25c

10lOc2215b55c52h42h2

20S31lc

121

lOcSblS3c4c1

103h

10551313

1032h2h5h

10S3c5SclhSh55c

32962.8132955.5332933.1332919.7832917.9132910.0532906.0732901.1132899.8632895.4232886.3832885.3332845.7732827.0132801.9632794.1232792.3732791.3832781.8132733.7232724.0132676.9432645.9032638.1232634.4632630.3532596.8832573.3932564.4732563.0732559.6432534.0632495.8032462.5932440.6032392.3932389.4032386.9232383.4532379.3632374.3532362.5732349.0632323.9332275.0432263.7832238.4332194.2332159.7132148.4732083.5132045.8232015.7032001.5131993.9431948.4431946.6731913.3131870.4631846.3731845.1531812.1731801.8431787.3731776.6431770.2831762.7931745.5931675.5531669.13

46519S12 -79437 S°1

46096112 -789811°/2

51848912 -846407/2

484965/2 -81059712

465193,2 -78981 °/2

52099 13/2 -84486 1312

496105,2 -81985,7/2

471735/2 -79437°312488283,2 -810675-12

479937/2 -80153°512

482591/2 -80253-3/2

504267/2 -82101-9/2

November 1974 1497SPECTRUM AND ENERGY LEVELS OF Eu III

APPENDIX. Spectral lines of Eu In -Continued

Wavelength Wavenumnber Wavelength Wavenumber(A) Intensity (cm_') Classification (A) Intensity (cm-') Classification

3164.9553167.7743170.5963170.9983178.0773178.8683183.7783185.8583191.4623194.3453206.3013206.5063208.1443208.9463209.5063213.8393224.8933225.2893226.0183230.4113241.5123244.7213259.5713262.4663280.9933294.1673303.5543317.233

342

50c1020bSOc

SblOb20c10SbS

101

lOblh2blhlh34533353h

31586.8831558.7731530.6831526.6931456.4731448.6431400.1431379.6431324.5531296.2831179.5831177.5931161.6731153.8831148.4431106.4530999.8330996.0330989.0230946.8830840.9030810.4030670.0430642.8230469.7930347.9430261.7230136.93

504267,2 -81985,712

52960,2 -84486°13/2496101,2 -81067 -/2496105,2 -810597°2518489,2 -83248°,,248259112 -79639 ,/488283,2 -80153°5/250805 712 -82101 1/2508057,2 -81985 7/2482591/2 -79437 3/2499051,2 -810675-12499055,2 -81059-7/25209913,2 -83248 ,/3518489/2 -829549,25296011,2 -83959 ,/2

488283,2 -79639 1/2

49610152 -80253 a/2

3330.7223341.7313344.2483352.8183357.3954595.0094837.9775061.6806347.1016666.3476772.2476790.4306943.3626976.0187005.7477221.8387225.1517386.8187611.6237690.4357750.5947'783.8697873.3307934.5618079.0718379.2128581.510

1251S3

1022

50113S1

30121

202111

1053

30014.8829916.0029893.4929817.0829776.4421756.6520664.0219750.7815750.8714996.5814762.0714722.5514398.2814330.8914270.0613843.0713836.7313533.9013134.1912999.5912898.6912843.5512697.6112599.6312374.2611931.0211649.76

28200-,2 -499569122862850/2 -492927,/2

32073 7,2-4706911,2

3230717/2 -47069 15/2

28200,712 -425307,2

32307 ,2-461501232314 M/2 -46150 13/2

32179 1 12 -45313,,, 232314 ,2 -453131112

282007,2 -408975,231954°u/2 -445539,232179 ,°,2 -445539,2319549,2 -438857,231745'7°2 -433955,2

49905S1 250805 7/2518489,,

-80253 3°12-81067 ^°3-81985°12