1 Infrared Spectroscopy of Ammonium Ion MG03: Sub-Doppler Spectroscopy of ND 3 H + Ions in the NH...
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Transcript of 1 Infrared Spectroscopy of Ammonium Ion MG03: Sub-Doppler Spectroscopy of ND 3 H + Ions in the NH...
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Infrared Spectroscopy of Ammonium IonInfrared Spectroscopy of Ammonium Ion
MG03:MG03: Sub-Doppler Spectroscopy of NDSub-Doppler Spectroscopy of ND33HH++ Ions in the NH Stretch Mode Ions in the NH Stretch Mode
MG04:MG04: Infrared Spectroscopy of Jet-cooled NDInfrared Spectroscopy of Jet-cooled ND22HH22++ Molecular Ions: Molecular Ions:
The Symmetric and Antisymmetric NH Stretch ModesThe Symmetric and Antisymmetric NH Stretch Modes
CHIH-HSUAN CHANG, Grant Buckingham, and David J. NesbittJILA, NIST, University of Colorado
Department of Chemistry and Biochemistry, University of Colorado at BoulderBoulder, CO 80309
International Symposium on Molecular Spectroscopy68th meeting, Jun17-21, 2013, OH
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IntroductionIntroduction
• NH4+ ion is a crucial species in acid-base chemistry
and aqueous solution
• Carrier of spectra in the Young Stellar Objects (YSO)
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Located approximately 12,000 light-years away from Earth, in the constellation Sagittarius
AstronomyAstronomy
Gibb et. al. The Astrophysical J. 536,347(2000)W. A. Schutte and R. K. Khanna, A&A, 398, 1049(2003)
NH4+
44
H3+
H3O+ OD3+HOD2
+H2OD+
Isotope-substituted Ion SpeciesIsotope-substituted Ion Species
NH2D2+NH4
+ NHD3+ NHD3
+ ND4+
• Symmetry reduction results in the multiple non-degenerate vibrations and intensity dilution
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Fundamental Vibration ModesFundamental Vibration Modes
Jacox and Thompson, PCCP, (7) 765, 2005 Intensity in unit of km/mol.
Oka group
Saykally group
Oka group
Saykally group
Nakanaga and Amano
Park et. al.(1996)
66
Frequency calibration Frequency calibration Polarization-stabilized HeNe laser Polarization-stabilized HeNe laserLaser scanning Laser scanning Fabry-Perot interferometer Fabry-Perot interferometerConcatenation Concatenation Marker cavity Marker cavity
Sub-Doppler Resolution Infrared SpectrometerSub-Doppler Resolution Infrared Spectrometer
• Absorption noise level ~ 1.310-3 %• Absorbance ~ 0.055 %• Signal to noise ratio ~ 45• Sub-Doppler resolution ~ 120 MHz (H2 gas)
Chemical reaction route : H2 + e- H2
+ + 2e-
H2+ + H2 H3
+ + H H3
+ + ND3 ND3H+ + H2
H3+
+ ND2H ND2H2+ + H2
Discharge Slit-jet
General Advantages: Sub-Doppler resolution (60 MHz) Rotational cooling (15 K) High density of radicals or cation.
mirrormirror
Slit jet
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Band Type Structure of TransitionBand Type Structure of Transition
b
c
//
1 6 1
Oblate Top (A = B > C)Asymmetric Top( = 0.27)
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Nuclear Spin StatisticsNuclear Spin Statistics
• ND3H+ ion
123 1total total 1 2 or total A A
1 210 1 8ns A A E
KK RotRot ggnsns
00 J even J even AA11 1111
J oddJ odd AA22 1111
3n3n±±11 EE 16163n3n±±33 AA1 1 + A+ A22 2222
ggnsns
KKa a + K+ Kc c = even= even 1515
KKaa+ K+ Kcc= odd= odd 2121
(e)(e) (v)(v) (r)(r) (ns)(ns) (total)(total)
aa11 aa11 aa11 bb22 bb1 1 or bor b22
aa11 aa11 bb11 aa11 bb1 1 or bor b22
aa11 aa11 bb22 aa11 bb1 1 or bor b22
aa11 aa11 aa22 bb22 bb1 1 or bor b22
• ND2H2+ ion
1 221 15ns A B
12 1total total 1 2 or total b b
12 1total total
total e v r ns
total e v r ns
1: ( =0, 1, 2...)
11: ( = ,...)
2
Boson particle I
Fermi particle I
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Global View Region of NH Modes Global View Region of NH Modes
ND2H2+
Symmetric mode(1)ND2H2
+
Antisymmetric mode(6)ND3H+
NH stretch mode(1) NDH3
+
Asymmetric mode(4)
1111
Stick Plot of Rotational StructureNDND22HH22
++ Antisymmetric mode ( Antisymmetric mode (vv66) )
NDND22HH22++ Symmetric mode( Symmetric mode(11))
NDND33HH++ NH stretch mode( NH stretch mode(11))
NDHNDH33++ Asymmetric stretch mode( Asymmetric stretch mode(44))
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Results of NDResults of ND33HH+ + Ion Ion
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• Q branch feature of parallel band• Ground state combination difference (GSCD)• Nuclear spin statistic• Some transitions show perturbation
High Resolution Jet-cooled SpectrumHigh Resolution Jet-cooled Spectrum
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Boltzmann Plot and Rotational TemperatureBoltzmann Plot and Rotational Temperature
2/( , ) (2 1) (2)
1ln ln ( , )
(2 1) (2)
rotE kTns
ns rot
S C g J K J HL e
Sg J K E
C J HL kT
Expected value 22 K=3 16 K=1, 2 11 K=0
NDND33HH++
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Fitting Results:Fitting Results:
B”B” 3.706595(26)3.706595(26)
C”C” 2.90692.9069
D”D”JJ 6.71(25)6.71(25)1010-5-5
D”D”JKJK 6.70(68)6.70(68)1010-5-5
D”D”KK 00
//
1
F(J,K)=BJ(J+1)+[C-B]K2DJJ4 DJKJ(J+1)K2 DKK4
B’B’ 3.65114(76)3.65114(76)
C’C’ 2.90102(48)2.90102(48)
D’D’JJ 2.893(62) 2.893(62) 1010-3-3
D’D’JKJK 2.360(14) 2.360(14) 1010-3-3
D’D’KK 7.15(92) 7.15(92) 101044
00 3316.8347(19)3316.8347(19)
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Results of NDResults of ND22HH22+ + Ion Ion
c
b
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Jet-cooled Spectrum of v6 Mode
NDND22HH22++
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Jet-cooled Spectrum of v1 Mode
NDND22HH22++
1919
Band Intensity for vBand Intensity for v66 and v and v11 Modes Modes
2/
2
(2 1)
ln ln(2 1)
JK Ka c
JK Ka c
JK Ka c a c
E kTins i
i
JK Ki
ns
S C g J e HL
S EC
g J HL kT
Bond-dipole model
I(Qantisym) / I(Qsym) = 2/1
2020
GroundGround 11 mode mode 66 mode modeAA 4.85675(5)4.85675(5) 4.80782(4)4.80782(4) 4.82922(4)4.82922(4)BB 3.96819(4)3.96819(4) 3.94615(6)3.94615(6) 3.94784(3)3.94784(3)CC 3.44667(5)3.44667(5) 3.44190(5)3.44190(5) 3.43182(5)3.43182(5)
JJ 101066 6.5(1.6)6.5(1.6) 13.0(1.2)13.0(1.2) 4.2(1.5)4.2(1.5)KK 101066 5.3(9.4)5.3(9.4) 20.7(12.4)20.7(12.4) 1.5(7.4)1.5(7.4)JJ 101055 6.5(3)6.5(3) 6.3(2)6.3(2) 6.2(2)6.2(2)JKJK 101055 4.8(9)4.8(9) 4.3(8)4.3(8) 3.6(9)3.6(9)KK 101044 1.18(9)1.18(9) 0.90(6)0.90(6) 1.34(6)1.34(6)
vv00 3297.5439(1)3297.5439(1) 3337.9050(1)3337.9050(1)
Fitting Results of NDFitting Results of ND22HH22++ Ion Ion
A-reduced Hamiltonian
( ) 2 2 2 4 2 2 4
2 2 2 2 2 2 2 2 22 ( ) ( ) ( )
Aeff a b c J JK a K a
J b c K a b c b c a
H AJ BJ CJ J J J J
J J J J J J J J J
~ 40 cm-1
2121
Theoretical CalculationTheoretical Calculation
NDND22HH22++ NDND33HH++
Exp.Exp. Cal.Cal. Exp.Exp. Cal.Cal. 11 3297.5439(1)3297.5439(1) 3297.63297.6 -0.056-0.056 3316.834(1)3316.834(1) 3311.43311.4 5.4345.43422
33
44
55
66 3337.9050(1)3337.9050(1) 3333.43333.4 4.5054.50577
88
99
Chem. Phys. Lett, 258, 129(1996)
2222
Jet-cooled Spectrum of NDHJet-cooled Spectrum of NDH33+ + ion ion
NDH3+
2323
Q branch of 4(E) Mode
T. Nakanaga, T. Amano , Can. J. Phys., 64, 1356 (1986)
Vibration angular momentuml-type doubling
SummarySummary• High resolution of jet-cooled spectra of NH stretch modes of
ND3H+(1) and ND2H2+(1,6) assigned for the first time
• Band origins and band types are determined
• Band intensity of v1 and v6 mode and bond dipole physical model
• Fingerprint in astronomy
N2H7+H5O2
+(Zundel or Eigen) ?
Further work will be extended into hydrogen bonded complexes
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AcknowledgementAcknowledgement
David J. NesbittDavid J. NesbittGrant BuckinghamGrant BuckinghamMelanie Roberts (Stony Brook)Melanie Roberts (Stony Brook)
Thank you for your attentionThank you for your attention
JILAJILA