1. VIBRONIC ANALYSIS FOR TRANSITION OF ISOPROPOXY Rabi Chhantyal-Pun, Mourad Roudjane, Dmitry G. Melnik and Terry A. Miller TD03

2. Motivation : Oxidation of Hydrocarbons * J. J. Orlando, G. S. Tyndall, T. J. Wallington, Chem. Rev. 103, 4657 (2003)

3. Jahn Teller Effect Pseudo Jahn Teller Effect Pseudo Jahn Teller Effect 355(10) cm -1 60.7(7) cm -1 Ramond et. al. J. Chem. Phys. 112, 1158 (2000) Rabi Chhantyal-Pun, Jinjun Liu and Terry A. Miller, TI14, MSS 2012 Columbus Jin et. al. J. Chem. Phys. 121, 11781 (2004) CH 3 O C2H5OC2H5O i-C 3 H 7 O Foster et. al. J. Phys. Chem. 90 6766 (1986) Motivation : Spectroscopy

4. XCH 2 CH 2 ONO / He General Valve ControllerDG535 Pulse Generator XeF Excimer Laser Nd:YAG Laser Sirah Dye Laser Nozzle T0T0 PMT Q-Switch Flash Lamp T 0 / GPIB T0T0 Lens Frequency Doubler XCH 2 CH 2 O NO Experiment : LIF Setup

5. 1 J. Liu, D. Melnik and T. A. Miller, To be published 12 0 0 12 1 0 12 2 0 12 3 0 12 4 0 CO stretch 574.4 cm -1 Carter et. al. J. Phys. Chem. A 104 9165 (2000) 104 112 1.62 1.37 118 114 x (b) z (c) y (a) -Cs plane (bc plane in the inset) contains central HCO atoms -TD-CAM-UB3LYP/6-31+G(d) Transition of Isopropoxy Method Excited State Rotational constants ABC UCIS/6-31+G(d)8.828.024.81 TD-UB3LYP/6-31+G(d)8.557.934.72 TD-CAM-UB3LYP/6-31+G(d)8.657.994.77 TD-UWB97X/6-31+G(d)8.648.004.77 Exp. 1 8.618.014.74

6. a TD-CAM-UB3LYP/6-31+G(d) b Pseudo Jahn-Teller active modes ModeSymmetry DescriptionCalc. a Exp. 10 b HCO bend1009950 11 CC stretch889862 12 CO stretch592569 13 CCCO umbrella463449 14 CCC bend351344 15 In-phase CH 3 torsion258237 26 b CO wag452357 27 Out-of-phase CH 3 torsion189211 27 1 0 15 1 0 14 1 0 26 1 0 27 2 0 13 1 0 15 2 0 11 1 0 10 1 0 d Band d is a hot band Transition of Isopropoxy

7. B̃ Ã X̃ ν 14 2ν 27 ν 13 2ν 15 ν 26 a’ a’’ a’ ν 27 ν 15 a’’ a’ Transitions to symmetric levels allowed within Born Oppenhiemer approximation governed by Franck Condon principle [FC bands] and those allowed vibronically by Herzberg-Teller mechanism [HT bands] ∆ν=+1 transitions in asymmetric modes (26 1 0 and 27 1 0 ) possible due to spin-vibronic mechanisms [SV bands] ν 12 a’ ν 10 a’ 60.7 cm -1 ν 11 a’ Transition of Isopropoxy

8. Spin-Vibronic Mixing Vibronic mixing pseudo Jahn Teller effect Spin orbit mixing Isolated excited state

9. Spin-Vibronic Transition Moment Symmetric level HT bands Asymmetric level FC bands Spin-Orbit mixing

10. Experimental spectra and simulation. Experimental Simulation 0 0 0 Band Dmitry G. Melnik, Terry A. Miller and Jinjun Liu, TD04, MSS 2013, Columbus

11. Full simulation, a,b, and c-type c-type (z) b-type (x) a-type (y) Transition Dipole moment 0 0 0 Band Dmitry G. Melnik, Terry A. Miller and Jinjun Liu, TD04, MSS 2013, Columbus x y z x z y TDMSim. c (z)0.95 b (x)0.31 a (y)1.00

12. FC Bands Rotational Contour ν 12 a’ [CO str.] ν 15 a’ [CH 3 torsion] TDMSim. c (z)0.95 b (x)0.31 a (y)1.00 TDMSim. c (z)0.95 b (x)0.31 a (y)1.00

13. ν 10 a’ [HCO bend] ν 13 a’ [CCCO umbrella] HT Bands Rotational Contour TDMSim. c (z)0.31 b (x)0.31 a (y)0.25 TDMSim. c (z)0.10 b (x)0.90 a (y)1.00

14. SV Band Rotational Contour ν 26 a’’ [CO wag] TDMSim. c (z)0.95 b (x)0.65 a (y)0.25

15. Detailed vibronic assignments performed for the t transition of isopropoxy with the aid of quantum chemistry calculations Transitions in stretch and torsion modes allowed within Born Oppenhiemer approximation governed by Franck Condon principle [FC bands] Transitions in bend modes allowed with vibronic Herzberg-Teller mechanism [HT bands] Spin-vibronic mechanism leads to ∆ν=+1 transition in the asymmetric CO wag mode [SV bands] Conclusion

16. Miller Group Members -Prof. Terry Miller (Advisor) -Neal Kline -Terrance Codd -Meng Huang Acknowledgement

17. Rotational Contours ν 10 a’ [HCO bend] ν 26 a’’ [CO wag] ν 13 a’ [CCCO umbrella] ν 12 a’ [CO str.] ν 15 a’ [CH 3 torsion]