Near Infrared Spectroscopy of H 3 + and CH 2 +
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Near Infrared Spectroscopy of H3+ and CH2
+
Takeshi Oka
Department of Chemistry and Department of Astronomy and AstrophysicsThe Enrico Fermi Institute, The University of Chicago
Jennifer L. Gottfried
J. Chem. Phys. 118, 10890 (2003) 121, 11527 (2004)
28th International Symposium on Free Radicals, September 5, 2005
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H3+
Jupiter
Interstellar
Galactic center
Rigorous theory
Astrophysics
Charm
M. Bawendi
Li Wei Xu
Ben McCall
Jennifer Gottfried
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Barrier to Linearity
2003
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0
2000
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6000
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12000
14000En
ergy
(cm-1
)
23
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23
2
20
22
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1
1+2
1+2
1
1
1+2
1+2
1+220 2
22
4 26
1+ 2
1+20
1+22
1+ 2
1+ 2
Vibrational Bands
Hot bandsOvertones
Forbidden transitionsCombination
bands
2 fundamental band1980 – Oka
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0
2000
4000
6000
8000
10000
12000
14000En
ergy
(cm-1
)
23
22
23
2
20
22
21
20
24
21
25
1
1+2
1+2
1
1
1+2
1+2
1+220 2
22
4 26
1+ 2
1+20
1+22
1+ 2
1+ 2
Vibrational Bands
22 new transitions above the barrier to linearity
Gottfried, McCall, Oka, JCP 2003
Lindsay, McCall, JMS 2001
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Near-Infrared Spectrometer
BurleighWA-1500 500 MHz
19 kHz
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> 104 increase in Sensitivity
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Only “impurity”: Rydberg H2
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Visible H3+ spectrum
Chris Neese, Chris Morong
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Predissociation Spectrum
Energy diagram showing significant energies of H3+
Pseudo-low resolution convolution of experimental data [Carrington, Kennedy, J. Chem. Phys. 81, 1 (1984)]
[Kemp, Kirk, McNab, Phil. Trans. R. Soc. Lond. A 358, 2403 (2000)]
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Progress of theoryNiels Bohr, 1919 First theoretical paperHenry Eyring, 1936 – 38 A series of five papersCoulson, 1936 MO theory, equilateral triangleHirschfelder, 1938 Isosceless triangleConroy, Christofferson, 1964 Modern ab initioCarney and Porter, 1976 Accurate VR predictionWatson, 1980 Traditional VR analysisSutcliffe and Tennyson, 1984 Variational calculationMeyer, Botschwina, Burton, 1988 Accurate PSNeale, Miller, Tennyson, 1996 3 million linesCencek, Rychlewski, Jaquet, Kutzelnigg, 1998 ΔPS<μHSchiffels, Alijah, Hinze, 2003 Truly first principle EVR
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Strong vibration-rotation interaction
ν2 2521.3 cm-1
B0 = 43.565 cm-1
C0 = 20.605 cm-1
q = - 5.372 cm-1
Oka, Phys. Rev. Lett. 45, 531 (1980)
ν1 3178.3 cm-1
Strong Fermi interaction
No off-diagonal Coriolis interaction
Giant ℓ-doubling/resonance
ζ = - 1
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New paradigm of spectral analysis
Electronic Vibration Rotation
Variational method PES 1 2 B, C, D, q…
Variational method
Tennyson, Sutcliffe, Miller Dinelli (London) Jacobi
Watson (Ottawa) r1, r2 r3
Kutzelnigg, Jaquet (Bochum)
Wolniewicz, Hinze, Alijah (Torun, Bielefeld) hyperspherical
Meyer, Botschwina, Burton (1988)
Lie, Frye (1992)
Röhse, Kutzelnigg, Jaquet, Klopper (1994)
Cencek, Rychlewski, Jaquet, Kutzelnigg (1998) ΔE < 10-6 H ~ 0.2 cm-1
Obs.
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[Alijah, Hinze, Wolniewicz, Ber. Bunsenges. Phys. Chem. 99, 251 (1995)][Schiffels, Alijah, Hinze, Mol. Phys. 101, 189 (2003).][Alijah, private communication (2003).][Neale, Miller, Tennyson, Astrophys. J. 464, 516 (1996).][Jaquet, Prog. Theor. Chem. Phys. 13, 503 (2003).]
Agreement with experiment
purely ab initio calculation!empirical correction for
nonadiabatic effects
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Expectation Values (Watson)
J=0-2, J=3-5, J=6-10, J=11-15, J=16-20
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Big picture H2: W. Kołos, L. Wolniewicz 1964 – 1975
J. Mol. Spectrosc. 54, 303 (1975)
H3+:Schiffels, Alijah, Hinze, Mol. Phys. 101, 175, 189 (2003)
Non-adiabatic and QED corrections missing
([H2]2)
H5+
JCP 86, 5072 (1987)
Saporoschenko JCP 42, 2760 (1964)
72 unassigned linesLindsay, McCall, JMS 210, 60 (2001)
What’s next ?
CH5+
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Interstellar Chemistry
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The enigma of CH+ chemistry
CH+ + H → C+ + H2 + 0.4 eVCH+ + H2→ CH2
+ + H + 1.7 eV
CH+ emission from the Red Rectangle
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V ben
d()/c
m-1
/degrees
A2B1~
X2A1~
2uBender and Schaefer 1971
Carter and Handy 1984Reuter and Peyerimhoff 1992Kraemer, Jensen, Bunker 1994Jensen, Brum, Kraemer, Bunker 1995Osmann, Bunker, Jensen, Kraemer 1997Bunker, Chan, Kraemer, Jensen 2001
2Πu state split by Renner – Teller effect
Rösslein, Gabrys, Jagod, Oka 1992Willitsch, Imbach, Merkt, 2002Willitsch, Merkt 2003
Isoelectronic to BH2
Herzberg, Johns, 1967
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C+ CH+ CH2+ CH3
+ CH4+ CH5
+H2
-HH2
-H
H2
-H
Chemistry of CH2+
He* + CH4 CH4+
CH3+
CH2+
Production, Penning ionization
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Chemical Discrimination
CH2+
“grass”H2*
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Π ← Σ (0, 8, 0) ← (0, 0, 0)
Ã(0,3,0)1 X̃(0,0,0)0
Ka
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Σ ← Π (0, 9, 0) ← (0, 1, 0)
Ã(0,4,0)0 X̃(0,0,0)1
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unassigned lines
Δ ← Π (0, 9, 0) ← (0, 1, 0)
Ã(0,3,0)2 X̃(0,0,0)1