P.F. Bernath et al- Laser Spectroscopy of CaBr: A^2-Pi-X^2-Sigma^+ and B^2-Sigma^+-X^2-Sigma^+...

8/2/2019 P.F. Bernath et al- Laser Spectroscopy of CaBr: A^2-Pi-X^2-Sigma^+ and B^2-Sigma^+-X^2-Sigma^+ Systems

1/19

J OURNAL OF MOLECULAR SPECTROSCOPY 8 8, 175- 193 (1981)

Laser Spectroscopy of CaBr: AT-X2x+ and B2Z+-X2x+ SystemsP. F. BERNATH~AND R. W. FIELD

Spectroscopy Laboratory and Departm ent of Chemist ry, M assachusetts Instit ute of Technology,Cambridge, Massachusetts 02139

ANDB. PINCHEMEL,? Y. LEFEBVRE, AND J. SCHAMPS

Laborat oire de Spectroscopic des Molt cules Diat om iques, E.R.A. 303, Vniv ersitC des Scienceset Techniques de Lill e, BBt. P5, 5%55 Villeneuv e ddscq, France

Laser excitation spectra have been recorded for Ca79Br and Cas*Br in the spectral regionW-630 nm. The use of a l-m monochromator as a narrow band pass filter (1-2 cm-l) hasallowed rotational analysis of the O-O, 1- 1, and 2-2 bands of the B2H+-X*2+ transition andthe O-O and 1- 1 bands of the A*lI-X*X+ transition. A few additional lines of the 0- 1, 1-2,l-0, and 2-l bands of the B-X system were used to obtain band origins for vibrationalanalysis. The main constants for Car8Br are (in cm-):

x2z+ A*II BZZT, 0 15 958.41 (10) 16 383.137 (6)% 285.732 (9) 288.56 (20) 285.747 (9)%X, 0.840 (4) - 0.954 (4)B, 0.094466141 (30) 0.0957343 (20) 0.0%5151 (20)ae o.oOO4O355140) 0.0004327 (20) 0.0084483 (15)ye (spin-rot.) 0.00301484 (50) - 0.068767 (79)Pe - -0.066834 (64) -A, - 59.175 (1) -(All uncertainties are lo.)

The usual isotope relations between the constants for Ca7sBr and Cas*Br are satisfied towithin 3~. The A and B states form a unique perturber pair with lea = 1.24.

I. INTRODUCTIONThe first CaBr spectra were observed by Walters and Barratt in 1928 (1). The

vibrational assignments appearing in Rosens tables (2) were made by Harrington(3) in 1942. The potential curves of the X, A, and B states are very similar, causingthe spectra to be extremely congested and overlapped. In addition, there are twoisotopes of bromine (79Br, 50.5%; 81Br, 49.5%) of approximately equal abundance.* Present address, Herzberg Institute of Astrophysics, National Research Council of Canada, OttawaKlA 0R6, Canada.* Visiting scientist at MIT.

175 0022-2852/81/070175-19$02.00/OCo p y r ig h t Q 1 98 1 b y Acad em ic Ress , In c .AU r ig h t s o f r ep r o d u c t io n in an y fo rm r e se rv ed .


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176 BERNATH ET AL.Consequently, no rotational analysis of the ATI-X22* andB*C+-X*X+ transitionshas been previously performed. The use here of a tunable single-mode, cw dyelaser, coupled with selective, narrow bandpass fluorescence detection, has allowedus to assign more than 2000 lines belonging to these two transitions. The A-Xand B-X transitions were simultaneously fit using a direct approach (4). Inaddition, some X-state microwave transitions, provided by Moller and Toning (5))were included in the final fits.

II. EXPERIME NTAL DETAILS

A preliminary study of the A-X and B-X systems was performed in Lille. TheCaBr radical was generated from CaBr, solid, in a King furnace at 1500-2000 K.Fluorescence was excited using a broadband (1 cm-) CR 590 rhodamine 6G dyelaser. Rotational assignments were made using laser-induced fluorescence spectrarecorded with a Jobin-Yvon THR 1500 spectrometer and calibrated against tho-rium lines. This technique has rather limited resolution, -0.05 cm-l, but the linesrecorded and assigned in this way served as a guide for our Doppler-limited laserexcitation experiments at MIT.

The excitation spectra were recorded using a Coherent model CR 599-21 dyelaser pumped with 4 W from the 5145-A line d Coherent CR 10 Ar+ laser. Weobtained single-mode powers (


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177aBr A% AND B*Z+-PH+

V(cm-I4 1I I I I 1 1 I r16396.0 1 6 3 9 5 . 5

FIG. 1.CaBr B*8+-X2X+ laser excitation spectrum. This figure illustrates the complexity of the B-Xsystem. One feature, near-overlap of R, lines of the O-O and l-l bands differing by only 1 J unit,would make rotational assignment of a nonlaser spectrum a formidable task. Trace 2 shows thespectrum obtained when total fluorescence is detected. Trace 1 shows the simplification into groups offour lines [O-O R,(J)nd l-l R,(J 1) for both Br isotopes] that occurs when narrow bandpassfluorescence detection is employed.

FIG. 2. CaBr ATI-X*H+ laser-induced fluorescence spectrum. A Fortrat diagram illustrates thestructure of the O-O (solid lines) and 1- 1 (dotted lines) bands of the A-X system. A l-cm- bandwidthlaser is tuned to the region of the Q,* and P, heads of the 1- 1 band. The resulting spectrum, shownat the top of the figure, includes a complex pattern of lines, the sources of which are indicated by theheavy portions of the Fortrat parabolas directly under the laser line. Each excitation line is accompaniedby a fluorescence line [shifted by approximately M(4N + 2)] originating from a common upperlevel. These lines appear above the heavy portions of the Fortrat parabolas for the conjugate branches.Note that the fluorescence is organized into distinct regions, each associated with a different excitationbranch and band combination, This is the basis for success of the selective fluorescence detectionlaser excitation method.


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178 BERNATH ET AL.TABLE I: Measured Line Positions for Ca79Br (in cm-, * denotes blended line)

TABLE IA. ATI,,,-XI+ System

fluorescence arising from simultaneous laser excitation of overlapped lines oftenoccurs in different spectral regions, as shown in Fig. 2. Thus, by using a mono-chromator as a narrow band filter, it is possible to select only the fluorescence froma particular branch of a chosen band. The excitation spectrum is then greatlysimplified, as shown by the top trace of Fig. 1. In this figure four branches arerecorded simultaneously (the R, branch of O-O and 1- 1 bands, for both isotopes)but the pattern is quite clear. By tuning the monochromator from one fluorescencefeature to another it is possible to separately record all of the branches occurring ina selected region of the spectrum. This technique has been previously applied toCaF (12), CaCl(Z3), NO* (14), and YO (15).


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CaBr ATI AND BY-XV

TABLE IA-Continued

A l-m monochromator with 1200-grooves/mm grating was used, in first order, asa filter. The bandpass of the monochromator was set at l-2 cm-l. A cooled RCAC31034 photomultiplier with photon counting electronics was used to detect thefiltered fluorescence.

III. RESULTSThe lines of the O-O and l- 1 bands of theA211-X28+ transition and the O-O, 1 - 1,

and 2-2 bands of the B*2+-X22+ transition of Ca7sBr are listed3 in Table I. Thecorresponding lines3 of CaBIBr are in Table II. The assignments were made usingstandard combination difference relations. Initially, mainly ground-state differ-s Tables I and II were prepar ed before the microwave data were available so all residuals were ob-

tained from fits that included only optical data. The change in observed-calculated from the combinedmicrowave-optical fits was typically 20.001 cm-l.


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180 BERNATH ET ALTABLE IB. A*&,,-X*2+ System

95.3e9* 295.589* 095.792* -195.999 -196.21, I96.425 196.6X* 297.074 I97.290 097.512 -297.735* -297.%1 -99e.19** -,I98.125 -898.630 -498.901 -599.,41* -299.386 -499.61, -299.887~ 4

ences were used since, by analogy with CaF and CaCl, the spin-rotation param-eter, y, was expected to be small.Lines were fit using a weighted (reciprocal, squared uncertainty), nonlinear,least-squares approach (direct approach) (4). The model Hamiltonian includesstandard 211 and 2 matrix elements (17). Lambda doubling and spin-rotation


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CaBr A*ll AND E*P+-X2X+

TABLE IC. B,Z+-JP Z+ System

181

:Bs:g$ :18.646. - 1 2m. 5 1 , * - , I7 8 . 1 0 2 - 3, B . ? B , - I7 8 . X6 - 27 8 . 0 5 , - 2n . 9 1 3 - 17 7 . 8 3 5 - 7, 7 . , , 9 - 1

77.45, -1077.295 -2,,.?I8 -3ll.L.5 -377.075 -4,7.006* - 1 0g : ; : : : :7 6 x 4 3 - 1x . 7 5 0 * - 6


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182 BERNATH ET AL.TABLE IC-Confinued

20.5

30.5

40.5

50.5

6 0 . 5

;:::: -:91.338 191.643 291.951 2;:::I:92.097 193.213 -693.540 -6:::::: -:;::z: ::::::;2g:;z :96.W 191.021 I97.390 49 7 . 1 6 5 - 29 8 . 1 4 0 - 39 8 . 5 2 1 - 29 8 . 9 0 , 09 9 . 2 9 5 1

16 3,,.8W Ix: :17.481 -1:::;:: :,l.l,Z -171.018 0:::: .:X.813 -316.131 17 6 . 6 5 8 - 2X. 5 8 1 - - ,7 6 . 5 2 0 ' 0x . 9 5 1 * - 3y &y

l

7 6 . 2 9 0 . 3A. 2 4 1 ' 51 6 . 2 0 1 ' I7 6 . 1 6 1 . 8

9 9 . 6 6 6 11 6 4 w. 0 8 0 0

effects were accounted for in each state with the usual second-order perturbationtheory expressions (4). The uncertainties of well resolved and blended lines aretaken at 0.005 and 0.01 cm-, respectively. For each isotope, the u = 0 levels ofB, A, andX states were fit simultaneously. Similar fits were made for u = 1. The2-2 band of the B-X system of Ca7sBr was fit alone with &, fixed at the valueobtained for the v = 0 level. For the B-X 2-2 band of Ca6Br, D" and y werefixed at values linearly extrapolated from u = 0 and 1 levels.After our optical analysis was complete, Mijller and Tiirring provided 40 micro-wave transitions for X2C+ V = 0, 1, and 2 of both isotopes. These data includehigh-N (-50) and low-N (-50) transitions of about 40-kHz (1.3 x 10e6 cm-) ac-curacy. These transitions were included in our final fits. The microwave transitionsgreatly improved the ground-state constants and reduced the correlation betweenground- and excited-state constants.


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183aBr ATI AND B*X+-X2X+TABLE II: Measured Line Positions for CaBr (in cm-, * denotes blended line)

TABLE IIA. ATI,,,-X2X+ System

The spectroscopic constants obtained from these fits are given in Table III.One extra digit is retained so that the constants will reproduce the original data.In order to perform a vibrational analysis of theB2Zf-X2X+ system, we recordeda few lines from bands of Av = r 1 sequences. These lines are listed in Table IV,The assignments were made by calculating spectra using the constants of Table IIIand estimated band origins obtained from the bandheads given in Table V. Theselines were then used to determine the band origins in Table VI.Table VII contains the equilibrium constants of X, A, and B states for bothisotopes. For the A state we used the Pekeris relationship (f8) to obtain w,x,.All Franck-Condon factors greater than 0.001 for vibrational levels less than v = 5 forthe A -X and B-X transitions appear in Table VIII. They were calculated usingstandard RKR (19) and FCF (20) programs from Ca7gBr equilibrium constants.


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184 BERNATH ET AL.TABLE IIA-Continued

IV. DISCUSSIONIn the calcium halides, the X2C+ state is derived from the slightly antibonding

4s~ molecular orbital centered on Ca+. The A211 and WZ+ states seem to form a4p complex, split by the ligand field of the halide. Thus the A -X and B-X transi-tions are the molecular analogs of the atomic resonance lines of a one valence elec-tron atom. By analogy with CaF (12,21) and CaCl(13,22), the A and B states areexpected to form a unique perturber pair (4) with 1 slightly greater than 1. Using1 = 1, the pure precession relationship (23) predicts y0 = p. = -0.0529 cm-l. Ascan be seen from Table III, y. = p. but both are 27% larger than this value. Thisimplies an feff = 1.24 for the expression

2ABML_a + 1)AJWI,,,

The simplest explanation of this is that the p complex contains some 3d characterwhich increases the I value toward 2. There is a trend in the calcium halides for anincrease in leff from 1.04 in CaF (12), 1.12 in CaCl (13) to 1.34 in CaI (24).The Franck-Condon factors for the A-X and B-X systems (Table VIII) are


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CaBr ATI AND B*8+-XV

TABLE IIB. A*I&X*~+ System


12/19

186 BERNATH ET AL.TABLE IIC. B2Z.-X*2+ System


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CaBr A2II AND B*Z+-X*XTABLE IIC-Continued

187

10.5

16 3e5.805 -286.028 -186.257 220.521.5

::::: :07.946 388.197xl.531.5 69.534 089.817 090.094 Cl

90.679 290.9w 99 1 . 2 7 5 * 591.570*-1

40.5 91.881 441.5 92.190 492.504* 5

16 386.281 186.559 -386.846 -28 7 . 7 3 2 10 8 . 0 3 2 08 8 . 3 3 6 - 288.646 -1ea.964 5

16 377.746 -3377.636 0377.522 03 7 7 . 4 1 7 - 23 7 7 . 3 2 0 23 7 7 . 2 2 0 1p 2 l 2 - ;3 i 9 4 7 03 7 6 . 2 6 1 - 43 7 6 . 7 0 9 43 7 6 . 7 1 3 33 7 6 . 6 3 9 1,76.574* 33X.516 93 7 6 . 4 5 3 ' 53 7 6 . 3 9 F 13 7 6 . 3 4 0 * 13 7 6 . 2 9 0 ' - 13 7 4 . 2 4 4 ' - 33 7 4 . 2 0 1 =- 59 7 6 . 1 6 1 * - 850.5 95.,w-2

similar to those for the other calcium halides. The vibrational structure of thetransitions, particularly for low V, is very diagonal. The Au Z 0 CaBr Franck-Condon factors are, respectively, larger and smaller than those for CaF (12) andCaI (24). As for the other calcium halides, the v # 0 sequences of CaBr becomesignificantly stronger at high v.Rotation-vibration analysis for two isotopes of CaBr allows a test of the usualisotopic relationships between parameters (16). The agreement between our ex-perimental isotopic parameter ratios and those predicted from the reduced massesis satisfactory (


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T

I

Sr

cCa

oCBncm-

6

DxIO8A

A

xIO

"

p

P

xIO

qxIO

O

Y

y

xIO

"

"

C

g

200

43

-OO

25

100

5

44

-0

25

B

0

I

00

7

43

-0

25

CBB

200

43

-0

24

100

000

43

43

1

-0

16

-0

24

C9

100

42

50

-6

17

-3

A

000

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51

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15

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-2

CB

10

41

B

50

-5

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41

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19

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-0

l

O

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-2

C9

IiE

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00

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00

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200

40

oo

100

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4

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b F

avuf

v=0

'Fx

avu

ln

ye

fmv=0a

1


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CaBr AW AND BzI+-Xz~+ 189


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190 BERNATH ET AL.TABLE V

Measured CaBr Bandheads (in A)

into true y and A,, provided that isotopic data are available.4 In our case, theisotopic A, values differ so slightly that this procedure is unlikely to give reliablevalues. The values of y0 (true) and AD obtained from isotopic data are:

y0 = 0.057 cm-A Do= 4.1 x 1O-5 cm-l.

The pure precession estimates of y,, (true) is (26):y0 = -p/2 = 0.034 cm-.

In order to check the significance of some of our small parameters, we have usedthe customary Pekeris (18) and Kratzer relations (16). The values are included inthe table of equilibrium constants (Table VII) and the agreement is 10% for w,x,and ~1% for D,.In addition, the program of Albritton ef al. (27) was used (along with the RKRcurve) in order to calculate D, values. The agreement is excellent (+O. 1%) even inthe excited states. For example, calculated values for the 2, = 0 levels of Ca7gBrare D, = 4.128 x lo+ cm- (X2X+), 4.220 x lo-* cm- (ATI), and 4.404 x 10v8cm- (B*Z+). The calculated values were fit to extract D, and & and these valuesare included in Table VII.Veseth (28) has derived a formula for estimating -yo,:

For 3/&,of Ca7gBr, this equation gives 2.25 X lo- cm-, which is close to the ex-perimental value, 2.58 x lo- cm-l. A similar expression for pn, gives poO = 2.16x lo- cm-. The unique perturber model requires p. = yo. The y. andp, valuespredicted by Veseths equations are in reasonable agreement with each other andfall between the respective experimental values. However, our phenomenologicalAD is a factor of 7 larger than the value predicted by Merers relationship (29).

This separation of y and AD is supposed to yield a y value which contains both spin-rotation andsecond-order spin-orbit contributions.


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CaBr A*U AND B*2+-X22+ 191TABLE VI

CaBr Band Origins (in cm-9B*E+-X*z+ A*&X*E+

vv C 2 1 ' g B , C P W C J 9 B r C P B ,O- l 1 6 0 9 9 . 0 6 6 ( 5 ) 1 6 1 0 0 . 2 3 7 ( Z )l - 2 1 6 1 0 0 . 5 3 3 ( 6 )o-o 1 6 3 8 3 . 1 1 4 ( l )l - l 1 6 3 8 2 . 9 0 1 ( l )2 - 2 1 6 3 8 2 . 4 6 2 ( l )1 - o 1 6 6 6 6 . 9 5 6 ( l ) 1 6 6 6 5 . 7 7 7 ( 2 )2 - l 1 6 6 6 4 . 8 3 5 ( 5 ) 1 6 6 6 3 . 6 7 4 ( 2 )

Nu mb e r s i n p a r e n t h e s e s a r e l o u n c e r t a i n t i e s .

TABLE VIIEquilibrium Constants (in cm-l)

Rnca7%r

1 5 %8 . 4 l ( l o ) c ' ~2 6 & %( 2 0 ) c ~ 4

4 . 2 1 4 2 ( 2 9 ) b4 . 2 1 3 ( 3 )

4 . 2 1 5 ( 7 )

1 4 . 4 ( Z )

- 0 . 0 6 6 8 3 4 ( 6 4 )- o . o o l o a ( s s )5 9 . 1 7 5 ( l ) d- o . 0 7 z ( l ) d

2 . 5 7 6 4

1 . 0 1 4 ( 1 4 ,0 . 0 9 4 9 3 7 8 ( 2 0 )0 . 0 0 0 4 2 6 9 ( 2 9 )

4 . 1 2 4 1 ( 3 7 ) b

4 . 1 4 5 ( 6 )

- 0 . 0 6 6 3 0 4 ( 7 0 )- 0 , 0 0 1 0 2 3 ( 7 1 )5 9 . 1 7 2 ( l ) d. o . 0 7 1 ( l ) d

2 . 6 7 6 4

@I*ca%r cd%

1 6 3 8 3 . 1 3 7 ( 6 ) 1 6 3 8 3 . 1 3 3 ( 8 )2 8 5 . 7 4 6 5 ( 9 2 ) 2 8 4 . 6 4 9 1 ( 1 4 3 )

0 . %4 0 ( 3 9 ) 0 . 9 4 2 8 ( 6 0 31 . 0 4 6 ( S ) l . O4 0 ( 4 )0 . 0 9 6 5 1 5 1 ( 2 0 ) 0 . 0 %7 1 6 6 ( 1 1 )0 . m 4 4 . 3 3 ( 1 5 ) 0 . 0 0 0 4 4 3 7 ( 8 )

4 . 3 . 3 ( 1 5 ) b 4 . 3 E . ( l r J ) b4 . 4 0 1 3 ( Z )

4 . 4 0 4 3 ( s ) 4 . 3 3 2 2 ( 4 )

5 . 7 ( l )

- 0 . %8 7 6 7 , 7 9 , - 0 . %8 1 1 5 ( 6 3 ,

- 4 . 2 4 ( %) - 4 . 6 4 1 4 5 )

2 . 5 6 7 6 9 ( 3 f 2 . %7 5 9 ( Z ) '


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192 BERNATH ET AL.TABLE VIII

Franck-Condon Factors for Ca79Br

0 1 2 3 4 50 0 . 9 1 9 0 . 0 7 5 0 . 0 0 6 - -1 0 . 0 8 0 0 . 7 7 4 0 . 1 2 9 0 . 0 1 6 0 . 0 0 2 -2 0 . 0 0 1 0 . 1 4 8 0 . 6 5 2 0 . 1 6 7 0 . 0 3 0 0 . 0 0 43 - 0 . 0 0 3 0 . 2 0 7 0 . 5 5 1 0 . 1 9 3 0 . 0 4 04 - - 0 . 0 0 6 0 . 2 5 7 0 . 4 6 6 0 . 2 0 85 _ _ _ 0 . 0 0 9 0 . 3 0 0 0 . 3 9 5

A2 n - X2 ~ +v

v 0 1 2 3 4 50 0 . 9 6 8 0 . 0 3 1 0 . 0 0 1 - -1 0 . 0 3 2 0 . 9 0 7 0 . 0 5 8 0 . 0 0 3 -2 - 0 . 0 6 2 0 . 8 5 1 0 . 0 8 0 0 . 0 0 6 -3 - 0 . 0 8 9 0 . 8 0 1 0 . 0 9 9 0 . 0 0 94 - 0 . 0 0 1 0 . 1 1 4 0 . 7 5 6 0 . 1 1 55 - 0 . 0 0 1 0 . 1 3 7 0 . 7 1 5

On l y v a l u e s g r e a t e r t h a n 0 . 0 0 1 a r e l i s t e d .

V. SUMMARYThe spectrum of CaBr is typical of alkaline earth halides and, more generally,transitions involving nonbonding electrons. Laser excitation spectroscopy with

narrow band detection allows the dense and badly overlapped spectrum to beanalyzed. Narrow band detection allows the experimenter to select the branchesand bands of greatest interest from the jumble of overlapped lines in the spectrum.The use of a continuously tunable single-mode, dye laser provides very high-qualitydata (+0.003-cm- accuracy).Simultaneous fitting of the A-X, B -X and microwave data reduces correlationsin the molecular constants. The combined fit molecular constants obey the ex-pected isotopic relations. The molecular constants allow accurate Franck-Condonfactors to be calculated. These Franck-Condon factors are required for the con-version of laser-induced fluorescence intensities into molecular populations inmonitored chemical reactions. The molecular constants, particularly lambda dou-bling and spin-rotation parameters, provide some insight into the orbital structureof CaBr. The A and B states form a unique perturber pair with feff = 1.24, suggestiveof 3d character in these states.

ACKNOWLEDGMENTSWe are greatly indebted to K. Moller and Professor T. Toning for providing us with their micro-

wave data in advance of publication. P. F. Bemath was supported, in part, by a Natural Sciencesand Engineering Research Council of Canada postgraduate fellowship. The MIT portion of this re-search was supported by Grants AFOSR-76-3056, NSF CHE-78-18427, and CHE-78-10178, NATO 1177.


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CaBr A2Il AND E *~-X*~+ 193Not e added in proof. Uncertainties for the X*2+ state constants, -yv (Table III), ye and oy (Table

VII), must be increased by a factor of 50 because unresolved hyperfine structure in the N - 15mm wavedata caused a systematic error in measured spin splittings. The effect on all other parameter valuesand uncertainties is negligible. Higher-precision radiofrequency measurements of X*2+ state hfs and yvalues by W. J. Childs, D. R. Cok, G. L. Goodman, and L. S. Goodman indicated the existence andsource of this problem.RECEIVED: November 13, 1980

REFERENCESI. 0. H. WALTERS AND S. BARRATT, Proc. Roy. Sot. Ser. A 118, 120-137 (1928).2. B. ROSEN, in International Tables of Selected Constants, Pergamon, New York, 1970.3. R. E. HARRINGTON,Ph.D. thesis, Berkeley, 1942.4. R. N. ZARE, A. L. SCHMELTEKOPF,W. J. HARROPP, AND D. L. ALBRITTON, . MO/. Spectrosc.

46, 37-66 (1973). The fitting routines used were generated by R. C. Stern and revised by T. H.Bergeman, R. A. Gottscho, and A. J. Kotlar.5. K. MILLER AND T. TARRING, private communication.

6. S. GERSTENKORNAND P. Luc, Atlas du Spectre dAbsorption de la Molecule dIode, CNRS,Paris, 1978.7. S. GERSTENKORNND P. Luc, Rev. Phys. Appl. 14, 791-794 (1979).

8. J. B. WEST, R. S. BRADFORD, JR., J. D. EVERSOLE, AND C. R. J O N E S , Rev. Sci. Instrum. 46,164- 168 (1975).

9. M. S. SOREM AND A. L. SCHAWLOW,Opt. Commun. 5, 148-151 (1972).10. P. F. BERNATH, P. G. CUMMINS, AND R. W. FIELD, Chem. Phy s. Lerf. 70, 618-620 (1980).II . P. F. BERNATH, B. PINCHEMEL, AND R. W. FIELD, J. Chem. Phys., in press.12. M. DULICK, P. F. BERNATH, AND R. W. FIELD, Cunad. J. Phys. 58, 703-712 (1980).13. L. E. BERG, L. KLYNNING, AND H. MARTIN, Phys. Ser. 21, 173-178 (1980).14. W. DEMTR~DER, in Case Studies in Atomic Physics (M. R. C. McDowell and E. W. Mc-

Daniels, Eds.), Vol. 6, North-Holland, Amsterdam, 1976.15. C. LINTON, J. Mol. Spectrosc. 69, 351-364 (1978).16. G. HERZBERG, Spectraof Diatomic Molecules, 2nd. ed., p. 107, Van Nostrand, New York, 1950.17. A. J. KOTLAR, R. W. FIELD, J. I. STEINFELD, AND J. A. COXON,J. Mol. Spectrosc. 80,86-108

(1980).18. C. L. PEKERIS. Phys. Rev. 45, 98-103 (1934).19. R. J. LEROY, private communication.20. R. N. ZARE.J. Chem. Phys. 40, 1934-1944 (1964).21. P. F. BERNATHAND R. W. F I E L D , J. Mol. Spectrosc. 82, 339-347 (1980).22. L. E. BERG, L. KLYNNING, AND H. MARTIN,Phys. Ser., in press (1980).23. R. S. MULLIKEN AND A. CHRISTY,Phys. Rev. 38, 87-119 (1931).24. D. E. REISNER, P. F. BERNATH, AND R. W. FIELD, J. Mol. Spectrosc., in press.25. J. M. BROWN AND J. K. G. WATSON,J. Mol. Spectrosc. 65, 65-74 (1977).26. J. M. BROWN, E. A. COLBOURN,J. K. G. WATSON,AN D F. D. WAYNE, J. Mol. Specrrosc. 74,294-318 (1979).27. D. L. ALBRITTON, W. J. HARROP, A. L. SCHMELTEKOPF,AND R. N. ZARE. J. Mol. Spectrosc.

46, 25-36 (1973).28. L. VESETH,J. Phys. E. 3, 1677-1691 (1970).29. A. J. MERER, Mol. Phys. 23, 309-315 (1972).

P.F. Bernath et al- Laser Spectroscopy of CaBr: A^2-Pi-X^2-Sigma^+ and B^2-Sigma^+-X^2-Sigma^+...

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Transcript of P.F. Bernath et al- Laser Spectroscopy of CaBr: A^2-Pi-X^2-Sigma^+ and B^2-Sigma^+-X^2-Sigma^+...