Polyatomic Molecular Relaxation in the Absence of Collisions

Abstract

The fluorescence rise time for dimethyl 1, 4-bis[2(4-methyl-5-phenyl-oxazolyl)] benzene (POPOP) and perylene molecules in the vapor phase is measured with a streak camera to be less than 20 and 30\ifmmode\pm\else\textpm\fi{}10 psec, respectively. These results are direct evidence that large polyatomic molecules can rapidly relax, even in the absence of collisions.