Optical process for selective excitation of isotopes and use in isotope separation

An optical process for the selective excitation of the molecules of one isotope in a mixture is claimed. A Raman-effective state is selected from the possible vibrational molecular excitation states. The mass-dependent energy E/sub v/ is determined for the isotope variety to be excited. The isotope mixture is exposed to the radiations of two monochromatic and co-linear beams of light of frequencies F1 and F2 where h(F1 - F2) = E/sub v/