Abstract
An experimental approach is described for obtaining highly enriched residual gas under IR multiphoton dissociation (MPD) of molecules in one cycle of irradiation. The approach is based on utilization of a pulsed molecular flow of small length (Δxfl ≤ 1cm). The use of a short flow length leads to high values of the dissociation yield of molecules (β≃1) in the whole volume of the flow. Owing to this, high enrichment of the residual gas is achieved in one cycle of irradiation. The isotopically‐selective dissociation of CF3I+ in the pulsed gasdynamic flow of a small length was studied. About 400‐fold enrichment of the 13C isotope in the residual gas was obtained following irradiation of a molecular flow of CF3I of natural isotope composition by a single laser pulse. The selectivity of dissociation was measured to be α ≥ 10
Highlights
The important problem in laser isotope separation by the IR multiphoton dissociation (MPD) of molecules [1, 2] is increase of selectivity, especially in the case of molecules with a small isotope shift.The most effective means to increase the selectivity of the dissociation is the cooling of the mixture of isotopomers in gasdynamic jets or flows [3,4,5]
The excitation energy fluence was 3.5 J/cm2. At such energy fluence the dissociation yield of CF3I is less than unity
The isotope-selective IR MPD of CF3I was studied in this fashion
Summary
The important problem in laser isotope separation by the IR MPD of molecules [1, 2] is increase of selectivity, especially in the case of molecules with a small isotope shift (like OsO4, UF6...). The most effective means to increase the selectivity of the dissociation is the cooling of the mixture of isotopomers in gasdynamic jets or flows [3,4,5]. Because of high chemical activity of the radicals formed in the course of dissociation of molecules and their small concentration in the flow conditions, it is rather difficult to realize the formation and effective collection of the products. In many cases it is preferable to dissociate molecules containing unwanted isotopes in the mixture and thereby enrich the desirable isotope in the residual gas
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