TEMPERATURE EFFECTS ON INTERSYSTEM CROSSING IN NAPHTHALENE,
Abstract
The fluorescence lifetime, t for naphthalene-h8 is the same in seven different solvents at room temperature. Upon cooling to 77K, however, t increases by 50 to 100 percent, depending upon the solvent matrix. For naphthalene-h8 in poly(methyl methacrylate) (PMM), we have also measured the temperature dependence of the fluorescence yield and of the quantum yield for intersystem crossing. These measurements show that variations in the rate constant for intersystem crossing are primarily responsible for the variations with temperature of t for naphthalene-h8 in PMM. Our results suggest that there may be another temperature-dependent nonradiative mode of decay of the fluorescent singlet state S1; however, our experiments do not permit an unambiguous verification of this decay mode. Identical measurements for naphthalene-d8 suggest that internal conversion from S1 to the ground singlet state is negligible at all temperatures. All of the temperature, solvent, and deuteration effects on t can be explained in terms of intersystem crossing from S1 to a triplet state slightly lower in energy than S1. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 21, 1969
- Accession Number
- AD0691026
Entities
People
- A. R. Calloway
- Peter F. Jones
Organizations
- The Aerospace Corporation