Accession Number : AD0668444

Title :   FLUORESCENCE OF DOPED CRYSTALS OF ANTHRACENE, NAPHTHALENE, AND PHENANTHRENE UNDER HIGH PRESSURES: THE ROLE OF EXCIMERS IN ENERGY TRANSFER TO THE GUEST MOLECULES,

Corporate Author : AEROSPACE CORP EL SEGUNDO CALIF MATERIALS SCIENCES LAB

Personal Author(s) : Jones,Peter F. ; Nicol,Malcolm

Report Date : FEB 1968

Pagination or Media Count : 36

Abstract : Fluorescence spectra of crystals of anthracene, naphthalene, phenanthrene doped with other polycyclic aromatic hydrocarbons have been studied at pressures as great as 50 kbar. The most significant effects of pressure on the spectra of the host crystals are a loss of intensity of the normal fluorescence with increasing pressure and the almost simultaneous appearance of a broad, featureless emission at energies about 3000 to 6000/cm lower than that of the normal fluorescence. This emission is assigned as the fluorescence of excimers formed upon optical excitation of the crystals under high pressure. The growth of the intensity of the excimer emission with increasing pressure, relative to the intensity of the normal fluorescence, is the same in doped crystals as in pure crystals. The intensities of the guest molecule fluorescences relative to the intensity of the normal host fluorescence in the various doped crystals increase with pressure at about the same rate as the intensity of the excimer emission. These observations are interpreted as indicating that excimers are the lowest-energy excited singlet species of aromatic molecular crystals at these pressures and that, when the excimer concentration is appreciable, the path of energy transfer is from the host via excimers to the guest. (Author)

Descriptors :   (*POLYCYCLIC COMPOUNDS, *FLUORESCENCE), ANTHRACENES, NAPHTHALENES, PHENANTHRENES, IMPURITIES, SOLID SOLUTIONS, EXCITATION, EMISSIVITY, MOLECULAR ENERGY LEVELS, EXCITONS, HIGH PRESSURE, SPECTROSCOPY

Subject Categories : Radiation and Nuclear Chemistry
      Atomic and Molecular Physics and Spectroscopy
      Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE