Terrance J. Codd*, John Stanton†, and Terry A. Miller* * The Laser Spectroscopy Facility, Department of Chemistry and Biochemistry The Ohio State University, Columbus, Ohio † Department of Chemistry, The University of Texas at Austin, Austin, Texas

Previous Work Hirota and colleagues reported observation of the and bands of the electronically forbidden transition a First broad range spectrum was taken by Deev et al. in an ambient CRDS experiment b Several bands were assigned in this work and evidence of strong JT coupling was reported Jacox and Thompson recorded FTIR spectra of the transition in a Ne matrix experiment c It significantly extended the spectral range and made several more assignments They reported evidence of weak JT coupling in 4 Most recently, Takematsu et al. have reported the observation of the vibronically forbidden origin of the transition and observed several hot bands d They refined the position of the origin band to cm -1 and reported a second peak roughly 8 cm -1 to the blue a. K. Kawaguchi, T. Ishiwata, E. Hirota, I. Tanaka. Chem. Phys. 231, 193 (1998). E. Hirota, T. Ishiwata, K. Kawaguchi, M. Fujitake, N. Ohashi, I. Tanaka. J. Chem. Phys. 107, 2829 (1997) b. A. Deev, J. Sommar, M. Okumura. J. Chem. Phys, 122, (2005). c. M. E. Jacox, W. E. Thompson. J. Phys. Chem. A, 114, (2010). d. K. Takematsu, N. C. Eddingsaas, D. J. Robichaud, M. Okumura, Chem. Phys. Lett., 555, (2013)

The “important” electronic states of NO 3 T HE A-X E LECTRONIC S PECTRUM OF NO 3 : S OME T HEORETICAL R ESULTS AND I DEAS John F. Stanton and Christopher S. Simmons 66 th OSU International Symposium on Molecular Spectroscopy, TJ03, June 20-24,2011 X̃2A2′X̃2A2′ A ̃ 2 E a ′′ A ̃ 2 E b ′′ B̃2Ea′B̃2Ea′ B̃2Eb′B̃2Eb′ B̃2Eb′B̃2Eb′ B̃2Ea′B̃2Ea′ A ̃ 2 E a ′′ X̃2A2′X̃2A2′ A ̃ 2 E b ′′

The “important” electronic states of NO , 4 JT A true multistate, multimode system with rich spectra and plenty of unsolved problems! T HE A-X E LECTRONIC S PECTRUM OF NO 3 : S OME T HEORETICAL R ESULTS AND I DEAS John F. Stanton and Christopher S. Simmons 66 th OSU International Symposium on Molecular Spectroscopy, TJ03, June 20-24,2011 X̃2A2′X̃2A2′ A ̃ 2 E a ′′ A ̃ 2 E b ′′ B̃2Ea′B̃2Ea′ B̃2Eb′B̃2Eb′ B̃2Eb′B̃2Eb′ B̃2Ea′B̃2Ea′ A ̃ 2 E a ′′ X̃2A2′X̃2A2′ A ̃ 2 E b ′′

≈≈≈ (ground state) ≈ NO 3 Vibronic Structure and Transitions Vibronically allowed transitions:

Nd:YAG pulse laser Raman Cell PD InGaAs Detector Ring-down cavity with slit-jet (absorption length ℓ = 5 cm) L = 67 cm Vacuum Pump ℓ R ~ – 1.3  m SRS (1 m, 18 atm H 2 ) 20 Hz, 8ns, 500 mJ MR-JC-CRDS Experimental Setup Sirah Dye Laser Filters 1 st or 2 nd Stokes 2-10 mJ,Δ ν~3 GHz Collimator 20 Hz, 8ns, 100 mJ 20 m Fiber Optic

wavenumber Room Temperature Jet Cooled Room Temperature vs Jet-Cooled Spectra Room temperature data from: A. Deev, J. Sommar, M. Okumura. J. Chem. Phys, 122, (2005).

a.u. wavenumber (cm -1 ) a.u. Jet-Cooled CRDS Data

Vibronic Hamiltonian,, for Nuclear Motion on the Electronic Potential Energy Surface, V 3D Plot of V showing Jahn-Teller Distortion

Quadratic Vibronic Hamiltonian T. A. Barckholtz, T. A. Miller, Int Rev in Phys. Chem.17, (1998) Harmonic Oscillator Linear Jahn-Teller Quadratic Jahn-Teller Cross-Quadratic Jahn-Teller Bi-linear Coupling

Vibronic Parameters Hamiltonian Parameters Experimental Parameters

D3D3 D3D3 D4D4 D4D4 c 3,4 b 1,3 b 1,4 K4K4 K 3,K 4 K3K3

a.u. wavenumber (cm -1 ) a.u. Vibronic Assignments

≈≈ ≈ Complementary of Parallel and Perpendicular Bands = 2 1 vibrational frequency (vibrational symmetry ) (4 1 vibronic levels x )

a.u. Comparison of Observed and Simulated Line positions

a.u. Comparison of Observed and Simulated Line positions

Comparison of Observed and Calculated (John Stanton) Line Positions (Parallel Bands Only) Further work clearly needed

Conclusions Over 20 Vibronic Bands in the Electronic Transition have been Observed and Assigned The Structure of the State has been Well Stimulated Including Linear and Quadratic Vibronic Interaction Terms Harmonic Frequencies for All 4 Vibrational Modes and Jahn- Teller Parameters for the e' Modes have been Obtained More Detailed Comparison to Calculations Forthcoming Imminently