TRIPLET STATES: METASTABILITY AND NON-RADIATIVE RELAXATION PROCESSES

Abstract

Author Institution: Department of Chemistry, Harvard University, Cambridge; Department of Chemistry University of California, Santa Barbara, California, 93106.We have examined, by means of a molecular beam electric resonance spectrometer with cesium target Auger effect detector, a number of aromatic, olefinic, acetylenic, carbonyl, and cyano compounds, for the existence of metastable states. The method consists of electron impact excitation of a beam of ground state molecules, followed by an 8O cm drift region to the Auger detector. The cesium detector is capable of observing electronic states 2eV above the ground state. The drift time is of the order of I msec. For a number of the species studied, a low lying triplet state has been established by electron energy loss measurements or absorption spectroscopy. Frequently, for these systems us do not observe a metastable species. A discussion of non-radiative processes effecting the lack of observable metestability will be presented. An experimental survey of chemical structure parameters governing the existence of triplet metastability is in progress and will be reported