The Huggins band of ozone:Assignment of hot bands

摘要

The "hot bands" of the Huggins band of ozone are assigned,in both the 218 K and the 295 K spectrum.The assignment is based on intensities calculated with three-dimensional vibrational wave functions for the electronic ground state (X) and the excited state (B).The hot-band structures in the 218 K spectrum all can be assigned to transitions starting from vibrational states with one quantum of stretching excitation in the ground electronic state.The 295 K spectrum shows new structures,which are due to transitions originating from vibrational states in the X state with two quanta of excitation of the stretching modes-despite very small Boltzmann factors.All structures in the low-energy range of the 295 K spectrum,even the very weak ones,thus can be uniquely interpreted.The significance of hot bands results from the strong increase of Franck-Condon factors with excitation of the stretching modes in both the lower and/or the upper electronic states,whose equilibrium bond lengths differ significantly.