Vibration–rotation fluorescence spectra of water in the ground electronic state

Laser-induced fluorescence has been used to investigate overtone states of water. Specific rovibrational states have been excited by a high-resolution Titanium:sapphire ring laser in the near-infrared region. The resulting fluorescence light around 3000–4000 cm−1 has been dispersed by a Fourier transformation interferometer. Rich collision-induced spectra are obtained. The specific nuclear spin states chosen by the laser excitation are conserved in collisional processes. Interesting vibrational intensity effects have been observed. Vibrational calculations with an exact kinetic energy operator in the curvilinear internal coordinate representation have been performed to compute emission intensities.