THE INTERSYSTEM CROSSING TO AND THE PHOSPHORESCENCE FROM THE INDIVIDUAL SUBLEVELS OF THE LOWEST TRIPLET STATE IN PYRAZINE AT 1.6K

Abstract

The observed exponential phosphorescence decay of pyrazine in cyclohexane or benzene matrix wt 77K, with lifetime of 18 millisec, is found to change into a complex decay below 10K. At 1.6K, the decay is resolved into three first-order decays of lifetimes 6, 130 and 400 millisec. These lifetimes are sensitive to changes in temperature and magnetic field strength. Two mechanisms are proposed to explain the observed results, but both propose that at 1.6K, the spin-lattice relaxation process between the sublevels of the triplet state is slow compared to the 6-millisec radiative lifetime of the tau(y) spin sublevel. The recent time-resolved polarization measurements of pyrazine phosphorescence in durene indicate that the second mechanism should be at least partially responsible for the observed results.

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Document Details

Document Type
Technical Report
Publication Date
Aug 01, 1968
Accession Number
AD0679238

Entities

People

  • Mostafa El-Sayed

Organizations

  • University of California, Los Angeles

Tags

Communities of Interest

  • Energy and Power Technologies
  • Materials and Manufacturing Processes

DTIC Thesaurus Topics

  • Chemistry
  • Electrons
  • Equations
  • Ground State
  • Integrals
  • Intensity
  • Internal Conversion
  • Low Temperature
  • Magnetic Fields
  • Measurement
  • Nitrogen
  • Probability
  • Quantum Properties
  • Radiation
  • Relaxation Time
  • Spin-Orbit Interaction
  • Steady State

Fields of Study

  • Physics

Readers

  • Chemistry (specifically Chemical Fluorescence)
  • Organic Chemistry
  • Quantum spin resonance or Electron Paramagnetic Resonance spectroscopy.