Accession Number : AD0682941

Title :   LIGHT ABSORPTION AND TRIPLET STATE CONCENTRATIONS IN DEPOPULATED SYSTEMS,

Corporate Author : AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS

Personal Author(s) : Judeikis,Henry S. ; Siegel,Seymour

Report Date : 08 JAN 1969

Pagination or Media Count : 30

Abstract : Analytical expressions were derived to characterize the absorption of light in optically thick samples containing aromatic molecules with long-lived electronic states. Competitive singlet - singlet and triplet - triplet absorptions are considered. The equations provide information about the light intensity and triplet-state molecular distributions across the sample path length. Additional expressions are given for the ground state depopulation (or triplet state concentration) averaged over the entire path length. This averaged value corresponds to experimentally observable quantities such as the electron spin resonance or phosphorescent emission intensities. In conjunction with the discussion on depopulation, the use of rise times to compute depopulation is considered for selected cases. For these cases it is shown that exponential rise times can be obtained in optically thick samples, but that the values of depopulation calculated from these rise times may bear little relation to the actual molecular triplet-state concentrations. (Author)

Descriptors :   (*AROMATIC COMPOUNDS, ABSORPTION SPECTRA), (*MOLECULAR ENERGY LEVELS, *ABSORPTION SPECTRA), ELECTRON PARAMAGNETIC RESONANCE, PHOSPHORESCENCE, GROUND STATE, ELECTRON TRANSITIONS

Subject Categories : Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE