Vibronic interactions in the NO3 radical

Abstract

The 1492 cm−1 band of NO3 previously reported [J. Chem. Phys. 82, 2196 (1985); 93, 951 (1990)] exhibits some features in the upper state which are difficult to understand if the band is purely vibrational, i.e., the degenerate N–O stretching band in the ground electronic state. The two most conspicuous anomalies are a finite spin-orbit coupling term which must be included in the Hamiltonian and a derived first-order Coriolis coupling constant which is smaller than the calculated value. These anomalous features are explained by the vibronic interaction with excited 2E′ electronic states.