The Fluorescence of Biacetyl Vapor at 4358A

Abstract

The fluorescence efficiency of biacetyl vapor when excited by radiation of wavelength 4358A is independent of the number of quanta absorbed per cubic centimeter per second, almost if not quite independent of biacetyl pressure, and decreases with increase in temperature but there seems to be a transition from one type of variation with temperature to another between 60° and 100°. Oxygen quenches the fluorescence strongly, and isobutylene quenches the fluorescence little or not at all. The marked difference in fluorescence behavior of biacetyl when excited by 4358A radiation from that when excited by 3660A radiation as pointed out by previous authors makes desirable an attempt to correlate fluorescence with photochemical behavior. Some suggestions are made with regard to mechanism.