Laser isotope separation

This patent describes a process for separating isotopes which comprises (1) irradiating a gaseous compound containing a mixture of isotopes with differing excitation energy levels with radiation of a first frequency which will selectively excite molecules of the compound containing a first isotopic species but not those molecules containing other isotopic species, and (2) subjecting the excited molecules to physical or chemical processes or a combination thereof. The first isotopic species contained in the excited molecules is separated from the isotopic species contained in the excited molecules. The improvement consists of adiabatically expanding the gaseous compound to form a highly cooled supersaturated gas in which spectrum simplification has occurred, flowing the supersaturated gas through a region wherein the supersaturated gas behaves as a continuous medium, irradiating the supersaturated gas in the region with the first frequency radiation, irradiating the supersaturated gas in the region with radiation having a second frequency sufficient to induce photochemical reaction in those molecules selectively excited by the first frequency radiation, and separating the reaction product produced thereby containing the first isotopic species from those molecules containing other isotopic species before substantial condensation occurs