Vibronic Analysis of the Ã2 E′′ State of No3 Radical

Abstract

A moderate resolution spectrum of the A 2 E state of the NO 3 radical has been obtained using jet-cooled cavity ringdown spectroscopy. The analysis of the vibronic structure of this spectrum has been undertaken using a quadratic Jahn-Teller Hamiltonian. All observed transitions have been assigned and unperturbed frequencies and Jahn-Teller coupling constants were determined by fitting the experimental spectrum using nonlinear least squares regression. We find evidence of strong Jahn-Teller coupling in this electronic state, particularly in the ν 3 mode. These results are compared to electronic structure calculations including terms up to fourth order. Calculated and experimental spectra are presented and critically compared.

FTIR Spectroscopy of NO3: Perturbation Analysis of the ν3+ν4 State

“…Vibronic interactions in the degenerate electronic states and among these states are interesting from theoretical and experimental points of views, as exemplified in a recent spectroscopic study of the A ̃2E″ state by Miller's group. 3 In the ground electronic state, the ν 3 +ν 4 band of NO 3 shows the strongest infrared absorption in the 1492 and 1472 cm −1 regions for 14 N and 15 N species, 4,5 respectively, because the ν 3 fundamental band (∼1060 cm −1 ) is predicted to have very weak intensity 6 due to cancellation of an infrared transition moment and a borrowed electronic transition moment through vibronic interaction with the B ̃2E′ state. In 2011, we reported the observation and analysis of the Fourier transform spectrum of the ν 3 hot band ν 3 + ν 4 ← ν 4 of 14 NO 3 in the 1127 cm −1 region, and molecular constants of the ν 3 + ν 4 and ν 4 states were determined.…”