Fluorescence spectra of laser-excited YO molecules in a H2---O2---Ar flame

Abstract

CW dye laser induced fluorescence emission and thermal emission spectra of YO-molecules in a 1 atm H2---O2---Ar flame of 2430 K were recorded simultaneously. Narrow band laser excitation was applied to four rotational lines in the (1, 1) Q-branch of the A2Π3/2→X2Σ+ transition and broadband excitation was applied to several separate Q-branches of the A2Π1/2,3/2→X2Σ+ transitions. From the differences between the fluorescence emission spectra and thermal emission spectra, we conclude that collisional de-excitation of an excited vibronic level takes place by vibrational relaxation, decay to the electronic ground state and by intermultiplet transfer in order of increasing probability.