Contribution of electronically excited states to the radiation chemistry of organic systems. Progress report, September 1, 1976--August 31, 1977
The fluorescence of N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) has been studied in the solvents n-hexane, methylcyclohexane, cyclohexane, isooctane, and tetramethylsilane for excitation energies below and above the photoionization threshold. Evidence is obtained for the existence, as a major intermediate in the photoionization process of a coherent but spatially diffuse excited state of TMPD. Electron impact spectra of NH/sub 3/ at low energies and 90/sup 0/ scattering angle has failed to reveal any evidence for a low-lying valence triplet. For simple saturated hydrocarbons, large angle electron-impact spectra also fail to reveal any evidence for low-lying valence triplet states. Therefore if valence-shell transitions exist at all in these molecules they must be imbedded at significantly higher energies in the absorption manifold. The fluorescence of the A ..-->.. X transition in ammonia-d/sub 3/ has been studied in the presence of saturated hydrocarbon perturbers up to densities of approximately 6 M. Essentially no change in fluorescence quantum yield is observed. This eliminates inelastic processes as contributing importantly to pressure broadening and to shifting of the A reverse arrow X transition. The pressure broadening and pressure shifting of the first 10 vibrational peaks in the A reverse arrow X (n/sub N/ ..-->.. 3s Rydberg) absorption of NH/sub 3/ has been studied using He, Ne, Ar, N/sub 2/, CH/sub 4/, CF/sub 4/ and SF/sub 6/ gases up to pressures of approximately 100 atm. Both blue and red shifts are observed depending on the nature of the perturber. A dependence of the magnitude of the shift on vibrational level is observed and attributed to important variations of the electronic wavefunction of the upper state with position of the nuclei.
- Research Organization:
- Univ. of Minnesota, Minneapolis, MN (United States)
- DOE Contract Number:
- EY-76-S-02-0913
- OSTI ID:
- 5183147
- Report Number(s):
- COO-913-68; TRN: 78-005412
- Country of Publication:
- United States
- Language:
- English
Similar Records
Contribution of electronically excited states to the radiation chemistry of organic systems. Progress report, December 1, 1981-November 30, 1984. [Tetramethyl-p-phenylenediamine]
Contribution of electronically excited states to the radiation chemistry of organic systems. Progress report, September 1, 1980-November 30, 1981
Related Subjects
AMINES
ENERGY SPECTRA
FLUORESCENCE
RESEARCH PROGRAMS
AMMONIA
ARGON
CARBON TETRAFLUORIDE
DEUTERIDES
HELIUM
METHANE
NEON
NITROGEN COMPOUNDS
RADIATION CHEMISTRY
SULFUR FLUORIDES
CYCLOALKANES
ELECTRON-MOLECULE COLLISIONS
ENERGY LEVELS
FLUORESCENCE SPECTROSCOPY
HEXANE
OCTANE
ORGANIC SOLVENTS
PHOTOIONIZATION
SILANES
ALKANES
CHEMISTRY
COLLISIONS
CRYOGENIC FLUIDS
DEUTERIUM COMPOUNDS
ELECTRON COLLISIONS
ELEMENTS
EMISSION SPECTROSCOPY
FLUIDS
FLUORIDES
FLUORINATED ALIPHATIC HYDROCARBONS
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
HALOGENATED ALIPHATIC HYDROCARBONS
HYDRIDES
HYDROCARBONS
HYDROGEN COMPOUNDS
IONIZATION
LUMINESCENCE
MOLECULE COLLISIONS
NITROGEN HYDRIDES
NONMETALS
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
RARE GASES
SILICON COMPOUNDS
SOLVENTS
SPECTRA
SPECTROSCOPY
SULFUR COMPOUNDS
400600* - Radiation Chemistry