The near-infrared bands of NO2 observed by high-resolution Fourier-transform spectroscopy

Fourier-transform absorption spectra of NO2 at 298 K were recorded between 9000-15000 cm(-1) at Doppler-limited resolution (0.012 cm(-1)), in the regi on near the (A) over tilde B-2(2)-(X) over tilde (2)A(1) conical intersecti on. The strong rovibronic bands are rather isolated and organized into poly ads which can be assigned by the number of bending quanta of the (A) over t ilde B-2(2) state, corresponding to the transitions with the largest Franck -Condon factors. Around 9735 cm(-1), where the origin of the (A) over tilde B-2(2)-(X) over tilde (2)A(1) vibronic band system is located and up to ab out 11200 cm(-1), hot bands dominate the spectrum. The complexity of the sp ectrum increases with energy due to an increasing density of (A) over tilde B-2(2) and (X) over tilde (2)A(1) vibrational levels, The rotational struc ture is dense and irregular as already observed for higher bands. (C) 1998 American Institute of Physics. [S0021-9606(98)02645-2].