Spectroscopic Studies of Pyrazine in Cryogenic Solutions.
Abstract
The differences between the npi transition of pyrazine and the pipi transition of naphthalene and benzene used as probes for the structure and dynamics of cryogenic solutions have been discussed in terms of hydrogen bonding (-N...H-C). Four main points can be made based on the above spectroscopic studies. (1) The addition of hydrogen bonding to the pyrazine/solvent interaction causes changes of the intermolecular potential as a function of temperature. Thus, the fluorescence spectra are shifted to higher energy as temperature increases. (2) Hydrogen bonding in the excited state tends to reduce the nonradiative processes and results in an activation energy for radiationless decay of roughly 2 kcal/mole for the (3)B(3u) state. (3) Solvent effects on the ground state and the (3)B(3u) state are quite similar. (4) In these cryogenic solvents the triplet state lifetime is greatly influenced by an impurity quenching process. It has, however, been possible to separate this rate from the intramolecular radiative and noradiative rates and to arrive at an impurity concentration estimate of 0.01 ppm in C2H6. The lifetime measured for the phosphorescence under these conditions is 4 msec which is within a factor of 4 of the longest lifetime measured for this system in a rigid glass.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 06, 1982
- Accession Number
- ADA116780
Entities
People
- Elliot R. Bernstein
- Fangxing Li
- Jung‐Hee Lee
Organizations
- Colorado State University