Accession Number : AD0676741

Title :   EFFECTS OF HIGH PRESSURES ON THE PHOSPHORESCENCE OF AROMATIC HYDROCARBONS AT 77K.

Descriptive Note : Technical rept.,

Corporate Author : CALIFORNIA UNIV SANTA BARBARA DEPT OF CHEMISTRY

Personal Author(s) : Offen,Henry W. ; Hein,David E.

Report Date : 10 SEP 1968

Pagination or Media Count : 18

Abstract : The phosphorescence spectra and lifetimes of naphthalene, naphthalene-d8, and 2-bromonaphthalene were studied in EPA at 77K as a function of pressure in the 0-40 kbar range. The triplet energy is lowered by approx. 1% at 30 kbar corresponding to a red shift of 7.5/cm/kbar for C10D8 and C10H8. Increasing pressures tend to blurr vibrational structure to a significant extent so that at 30 kbar only two broad bands separated by approx. 1400/cm remain for these three compounds. The triplet lifetimes at 30 kbar are shorter than at 1 atm by 10, 30, and 50% for bromonaphthalene, naphthalene, and naphthalene-d8, respectively. The pressure-induced enhanced electronic relaxation is discussed in terms of the 'activation volume' parameter. The difference in the pressure response of the C10D8 and C10H8 triplet decay is attributed to an increase in the vibrational overlap factor of deuterated naphthalene under pressure, leading to higher radiationless transition rates in this molecule. (Author)

Descriptors :   (*POLYCYCLIC COMPOUNDS, *PHOSPHORESCENCE), AROMATIC COMPOUNDS, HYDROCARBONS, NAPHTHALENES, DEUTERIUM COMPOUNDS, HALOGENATED HYDROCARBONS, BROMINE COMPOUNDS, MOLECULAR ENERGY LEVELS, BAND SPECTRA, RELAXATION TIME, ELECTRON TRANSITIONS, HIGH PRESSURE, CRYOGENICS

Subject Categories : Radiation and Nuclear Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE