Photophysical processes in the vapour phase measured by the optic–acoustic effect. Part 6.—Analysis for photofragmentation and photocombination with examination of mass and thermal diffusion to the cell walls

Abstract

Following gas-phase photofragmentation in the spectrophone the resultant acoustic signal is due to the increase in particle density as well as the concomitant release of translational energy. The relative magnitudes of these two contributions are examined theoretically and the effect of mass diffusion to the walls on the amplitude and phase of the acoustic signal is considered. Similar equations for the decrease in particle density due to photocombination are briefly discussed. By analogy with the mass diffusion analysis, thermal diffusion to the walls is examined and calculations on the amplitude and phase effects of such thermal loss are given.