Infrared laser single photon absorption reaction chemistry in the solid state. I. The system SiH4ndash;UF6a)

摘要

The reaction between SiH4and UF6under thermal gas phase and photon initiated conditions in cryogenic matrices has been investigated. The gas phase thermal reaction begins at 130ndash;140deg;thinsp;C producing HF, SiH3F, and a solid uranium fluoride product. When the UF6is matrix isolated within SiH4at 12 K and exposed to low power infrared radiation of 25 mW cmminus;2using laser emissions resonant with the ngr;3band of UF6, a reaction also occurs. This reaction produces SiH3F, UF5, and UF4as products. The same reaction is also catalyzed using a broad band incoherent source with a photon flux density of 10 mgr;W cmminus;2. The activation energy for the photoreaction (1.8 kcal molminus;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 configurationsndash;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.