Near Infrared Spectroscopy of H 3 + and CH 2 + Takeshi Oka Department of Chemistry and Department of Astronomy and Astrophysics The Enrico Fermi Institute, The University of Chicago Jennifer L. Gottfried J. Chem. Phys. 118, (2003) 121, (2004) 28 th International Symposium on Free Radicals, September 5, 2005

H3+H3+ Jupiter Interstellar Galactic center Rigorous theory Astrophysics Charm M. Bawendi Li Wei Xu Ben McCall Jennifer Gottfried

Barrier to Linearity 2003

2323 2222 2323 2 2020 2222 2121 2020 2424 2121 2525 11   1+21+2 1 11  1+21+2 1+21+2 2020 2222 2424 26     2 Vibrational Bands Hot bands Overtones Forbidden transitions Combination bands 2 fundamental band 1980 – Oka

2323 2222 2323 2 2020 2222 2121 2020 2424 2121 2525 11   1+21+2 1 11  1+21+2 1+21+2 2020 2222 2424 26     2 Vibrational Bands 22 new transitions above the barrier to linearity Gottfried, McCall, Oka, JCP 2003 Lindsay, McCall, JMS 2001

Near-Infrared Spectrometer Burleigh WA MHz 19 kHz

> 10 4 increase in Sensitivity

Only “impurity”: Rydberg H 2

Visible H 3 + spectrum Chris Neese, Chris Morong

Predissociation Spectrum Energy diagram showing significant energies of H 3 + 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 theory Niels Bohr, 1919 First theoretical paper Henry Eyring, 1936 – 38 A series of five papers Coulson, 1936 MO theory, equilateral triangle Hirschfelder, 1938 Isosceless triangle Conroy, Christofferson, 1964 Modern ab initio Carney and Porter, 1976 Accurate VR prediction Watson, 1980 Traditional VR analysis Sutcliffe and Tennyson, 1984 Variational calculation Meyer, Botschwina, Burton, 1988 Accurate PS Neale, Miller, Tennyson, million lines Cencek, Rychlewski, Jaquet, Kutzelnigg, 1998 ΔPS<μH Schiffels, Alijah, Hinze, 2003 Truly first principle E VR

Strong vibration-rotation interaction ν cm -1 B 0 = cm -1 C 0 = cm -1 q = cm -1 Oka, Phys. Rev. Lett. 45, 531 (1980) ν cm-1 Strong Fermi interaction No off-diagonal Coriolis interaction Giant ℓ-doubling/resonance ζ = - 1

New paradigm of spectral analysis ElectronicVibration Rotation Variational method PES 1 2 B, C, D, q… Variational method Tennyson, Sutcliffe, Miller Dinelli (London) Jacobi Watson (Ottawa) r 1, r 2 r 3 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 < 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 H 2 : W. Kołos, L. Wolniewicz 1964 – 1975 J. Mol. Spectrosc. 54, 303 (1975) H 3 + :Schiffels, Alijah, Hinze, Mol. Phys. 101, 175, 189 (2003) Non-adiabatic and QED corrections missing ([H 2 ] 2 ) H5+H5+ JCP 86, 5072 (1987) Saporoschenko JCP 42, 2760 (1964) 72 unassigned lines Lindsay, McCall, JMS 210, 60 (2001) What’s next ? CH 5 +

Interstellar Chemistry

The enigma of CH + chemistry CH + + H → C + + H eV CH + + H 2 → CH H eV CH + emission from the Red Rectangle

V bend (  )/cm -1  /degrees A2B1A2B1 ~ X2A1X2A1 ~ Bender and Schaefer 1971 Carter and Handy 1984 Reuter and Peyerimhoff 1992 Kraemer, Jensen, Bunker 1994 Jensen, Brum, Kraemer, Bunker 1995 Osmann, Bunker, Jensen, Kraemer 1997 Bunker, Chan, Kraemer, Jensen Π u state split by Renner – Teller effect Rösslein, Gabrys, Jagod, Oka 1992 Willitsch, Imbach, Merkt, 2002 Willitsch, Merkt 2003 Isoelectronic to BH 2 Herzberg, Johns, 1967

C + CH + CH 2 + CH 3 + CH 4 + CH 5 + H2H2 -H H2H2 H2H2 Chemistry of CH 2 + He * + CH 4  CH 4 + CH 3 + CH 2 + Production, Penning ionization

Chemical Discrimination CH 2 + “grass”H2*H2*

Π ← Σ (0, 8, 0) ← (0, 0, 0) Ã(0,3,0) 1  X̃(0,0,0) 0 KaKa

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