It is shown that the efficiency of classical gas-dynamic isotope separation can be strongly improved with the aid of a relatively weak cw infrared laser. Irradiation in the collisional region of a free jet of S${\mathrm{F}}_6$ diluted in argon with a 20-W C${\mathrm{O}}_2$ laser leads to an increase in the overall enrichment factor $\alpha$ from about 1.01 to nearly 2, at conditions that have not yet been completely optimized. Efficient isotopically selective condensation is demonstrated for the first time, the inhibition of homogeneous condensation being due to the selective vibrational excitation of one S${\mathrm{F}}_6$ isotopomer.

• Received 18 August 1983

DOI:https://doi.org/10.1103/PhysRevLett.52.522