Accession Number : AD0605613

Title :   TRIPLET-TRIPLET ABSORPTION IN SENSITIZED SOLVENT DECOMPOSITION,

Corporate Author : AEROSPACE CORP EL SEGUNDO CALIF

Personal Author(s) : Siegel,S. ; Eisenthal,K.

Report Date : 22 MAY 1964

Pagination or Media Count : 1

Abstract : The decay of the steady-state EPR signal from naphthalene triplet-state molecules in ether and other glasses under continuous near-ultraviolet irradiation at 77K was examined in some detail. It was shown that free radicals are produced by sensitized solvent decomposition at the same rate as the disappearance of the triplet-state EPR signal. Also, it was demonstrated that the latter decay process has a first-order dependence upon naphthalene concentration and that it exhibits a dependence upon excitation intensity, which is consistent with a two-photon absorption mechanism. The experimental results are discussed in terms of a model that involves the resonant transfer of energy from a highly excited triplet state of naphthalene to the solvent. Excitation of the excited triplet state took place via the absorption of a photon by a naphthalene molecule in its lowest triplet state. The free radicals were produced by the decomposition of the sensitized solvent molecule. It is believed that the naphthalene molecule is not destroyed in this process but that the EPR signal decay arises from a radicalmolecule inter-action which effectively shortens the lifetime of the triplet state. (Author)

Descriptors :   (*ORGANIC SOLVENTS, DECOMPOSITION), ATOMIC ENERGY LEVELS, PARAMAGNETIC RESONANCE, EXCITATION, POLYCYCLIC COMPOUNDS, FREE RADICALS, ABSORPTION, ENERGY, SENSITIVITY, PHOTONS, ETHERS, MOLECULES

Distribution Statement : APPROVED FOR PUBLIC RELEASE