Relaxation and vibrational fluorescence of WO in solid neon

Studies of laser-induced fluorescence of tungsten oxides in solid neon at 6 K provide interesting insights into the mechanisms of WO relaxation. The relaxation occurs by interelectronic cascade between the vibrational manifolds of excited electronic states, eventually reaching the v″=7 of the ground electronic state. Remarkably, for the heavy WO oxide, the non-radiative processes are surprisingly inefficient, with relaxation in the ground state apparently occurring predominantly by sequential vibrational fluorescence. The relaxation pathways of WO are discussed and compared with relaxation in lighter, first-row molecules exemplified by CN.