Enrichment of boron, carbon, and silicon isotopes by multiple-photon absorption of 10.6-μm laser radiation

Abstract

The polyatomic molecules SF₆, BCl₃, CF₂Cl₂, and SiF₄ have been irradiated in the presence of H₂ or N₂ using intense focused CO₂ laser pulses. All four of the polyatomic molecules underwent isotopically selective reactions showing depletion of the isotopic forms irradiated. The best enrichment was achieved with SF₆; however, all systems showed similar behavior with regard to pressure and irradiation time. Both BCl₃ and SiF₄ showed evidence of isotopic rescrambling reactions that occurred on about a 1‐h time scale. The mechanisms of the absorption process are believed to be enabled by the large density of states in the vibrational manifold of polyatomic molecules.