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

H3+

Jupiter

Interstellar

Galactic center

Rigorous theory

Astrophysics

Charm

M. Bawendi

Li Wei Xu

Ben McCall

Jennifer Gottfried

Barrier to Linearity

2003

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

Hot bandsOvertones

Forbidden transitionsCombination

bands

2 fundamental band1980 – Oka

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

Near-Infrared Spectrometer

BurleighWA-1500 500 MHz

19 kHz

> 104 increase in Sensitivity

Only “impurity”: Rydberg H2

Visible H3+ spectrum

Chris Neese, Chris Morong

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)]

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

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

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.

[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

Expectation Values (Watson)

J=0-2, J=3-5, J=6-10, J=11-15, J=16-20

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+

Interstellar Chemistry

The enigma of CH+ chemistry

CH+ + H → C+ + H2 + 0.4 eVCH+ + H2→ CH2

+ + H + 1.7 eV

CH+ emission from the Red Rectangle

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

C+ CH+ CH2+ CH3

+ CH4+ CH5

+H2

-HH2

-H

H2

-H

Chemistry of CH2+

He* + CH4 CH4+

CH3+

CH2+

Production, Penning ionization

Chemical Discrimination

CH2+

“grass”H2*

Π ← Σ (0, 8, 0) ← (0, 0, 0)

Ã(0,3,0)1 X̃(0,0,0)0

Ka

Σ ← Π (0, 9, 0) ← (0, 1, 0)

Ã(0,4,0)0 X̃(0,0,0)1

unassigned lines

Δ ← Π (0, 9, 0) ← (0, 1, 0)

Ã(0,3,0)2 X̃(0,0,0)1