Accession Number : AD0679980

Title :   INTERSYSTEM CROSSING IN PYRENE -h(10) AND PYRENE -d(10).

Descriptive Note : Rept. for Mar-Aug 68,

Corporate Author : AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS

Personal Author(s) : Jones,Peter F. ; Siegel,Seymour

Report Date : OCT 1968

Pagination or Media Count : 13

Abstract : The phosphorescence intensity, phosphorescence lifetime, and fluorescence lifetime of pyrene -h(10) and pyrene -d(10) were measured as functions of temperature from 80K to 300K. Using this data, we determine the temperature dependence of the rate constant for intersystem crossing. We find that there are two different routes for intersystem crossing from the lowest excited singlet state S(1) to the lowest triplet state T(o). In addition to a thermally activated transition from S(1) to the first excited triplet state T(1), intersystem crossing occurs directly from S(1) to T(o). Below 100K only the direct transition S(1) to T(o) can compete with the radiative decay of S(1). (Author)

Descriptors :   (*PHOSPHORESCENCE, *POLYCYCLIC COMPOUNDS), (*FLUORESCENCE, POLYCYCLIC COMPOUNDS), AROMATIC COMPOUNDS, DYNAMICS, MOLECULAR ENERGY LEVELS

Subject Categories : Radiation and Nuclear Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE