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Infrared laser single photon absorption reaction chemistry in the solid state. I. The system SiH/sub 4/--UF/sub 6/ a)

Journal Article · · J. Chem. Phys.; (United States)
OSTI ID:6281367

The reaction between SiH/sub 4/ and UF/sub 6/ under thermal gas phase and photon initiated conditions in cryogenic matrices has been investigated. The gas phase thermal reaction begins at 130--140/sup 0/ C producing HF, SiH/sub 3/F, and a solid uranium fluoride product. When the UF/sub 6/ is matrix isolated within SiH/sub 4/ at 12 K and exposed to low power infrared radiation of 25 mW cm/sup -2/ using laser emissions resonant with the ..nu../sub 3/ band of UF/sub 6/, a reaction also occurs. This reaction produces SiH/sub 3/F, UF/sub 5/, and UF/sub 4/ as products. The same reaction is also catalyzed using a broad band incoherent source with a photon flux density of 10 ..mu..W cm/sup -2/. The activation energy for the photoreaction (1.8 kcal mol/sup -1/) is considerably lower than the thermal activation barrier for the gas phase reaction. These experiments are part of the bases for uncovering a process of photochemistry of reactants in fixed relative configurations--single photon absorption reaction chemistry in the solid state (SPARCSS). This process is a manifestation of a previously unrecognized, general matrix phenomenon in which spatial configurations dramatically affect potential energy surfaces for reaction.

Research Organization:
Lawrence Livermore Laboratory, University of California, Livermore, California 94550
OSTI ID:
6281367
Journal Information:
J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 70:7; ISSN JCPSA
Country of Publication:
United States
Language:
English