Excited Triplet States of Some Polyatomic Molecules. I

Molecules in their metastable triplet state are obtained by intense ultraviolet excitation, and the absorption spectrum of the excited molecules is then measured. The conditions needed to obtain the required concentration of excited molecules are shown, and a method for determining this concentration is developed. This enables one to determine the extinction coefficient for the triplet-triplet transition and is an aid in characterizing the new state. The methods are applied to a number of compounds having long-lived triplet states.