1. Meng Huang, Anne B. McCoy and Terry A. Miller Department of Chemistry and Biochemistry The Ohio State University CH 2 XOO Systems (X = Cl, Br, I) FD05/06 9:38 AM

2. In combustion and atmospheric chemistry, alkyl peroxy radicals are important intermediates Oxidation of NO to NO 2 (Formation of Ozone) Formation of acid rain Reaction intermediate of fossil fuels combustion Methyl peroxy is the simplest alkyl peroxy radical The methyl group torsion in methyl peroxy provides good system for studying the effect of large amplitude motion

3. Fourier Transform Infrared Spectrum of CH 3 OO Radical in Mid-IR Range from Yuan-Pern Lee’s Group (T ~ 300K, Resolution ~ 0.15 cm -1 ) Experimental Results (cm -1 ) Harmonic Values (cm -1 ) 2954.33074.5 3021.43169.1 3032.33181.3 --140.3 Fourier Transform Infrared Spectroscopy of CH 3 OO Radical in Mid-Infrared Range Kuo-Hsiang Hsu and Yuan-Pern Lee Meng Huang and Terry A. Miller MSS, 2013

4. Parameters (cm -1 ) A’’1.730 B’’0.379 C’’0.330 A’1.726 B’0.379 C’0.330 a:b:c0.91:0.09:0 T R = 300K; ν tor = 140.3 cm -1 B3LYP/aug-cc-pVTZ Precursor Absorption Frequency(cm -1 )

8. G. M. P. Just, A. B. McCoy, T. A. Miller J. Chem. Phys. 127, 044310 (2007) Sim Exp

9. G. M. P. Just, A. B. McCoy, T. A. Miller J. Chem. Phys. 127, 044310 (2007) J. T. Hougen, I. Kleiner, M.Godefroid J. Mol. Spectrosc. 1994, 163, 559.

12. Ab initio calculation at the B3LYP/aug-cc-pVTZ level of theory Frequency(cm -1 )

13. Ab initio calculation at the B3LYP/aug-cc-pVTZ level of theory

15. No significant effects on the ground state

16. Ab initio calculation at the B3LYP/aug-cc-pVTZ level of theory

17. Strong coupling between v 2 + nv tor and v 9 /v 1 + (n-1) v tor

18. Energy Diagram

19. Energy Diagram – The First Torsional Sequence Band Uncoupled EigenvaluesEigenvalues with Couplings Blue shift

20. Experiment al Results (cm -1 ) 2954.3 3021.4 3032.3 ? The first torsional band has to be shifted to the blue. 67.1 cm -1 Frequency(cm -1 )

21. Energy Diagram

22. Energy Diagram – The First Torsional Sequence Band Uncoupled EigenvaluesEigenvalues with Couplings Increase in tunneling splitting! Blue shift Red shift

23. The simulation of the rotational contour with the torsional sequence bands Frequency(cm -1 )

24. The simulation of the rotational contour with the torsional sequence bands Frequency(cm -1 )

25. A reduced dimensional model including CH stretches and CH 3 torsion is used to calculate the torsional sequence band structure on ν 2 band of CH 3 OO radical. The structure depends on the accidental degeneracies of the ν 2 + nv tor with respect to ν 9 /ν 1 + (n-1) v tor. The increasing of the tunneling splittings for the sequence bands, which are the result from the coupling, could lead to possible broadening effect of the Q-branch of rotational structure. Under the current model, it is still hard to simulate the entire rotational contour of the ν 2 band. However, couplings from other degrees of freedom such as Fermi resonance may also contribute to the broadening effect. ModeFreq Difference(cm -1 )Cubic Coupling Constants(cm -1 ) ν 2 /2ν 4 83.390129.475 ν 2 /2ν 5 165.644215.906

26. Dr. Anne B. McCoy Zhou Lin Bernice Opoku- Agyeman Laura C. Dzugan Melanie L. Marlett Jason F. Ford Scott M. Garner Dr. Terry A. Miller Henry Tran Dr. Y. P. Lee