Method for isotope-selective vibrational excitation of a gaseous

Abstract

In an isotope-separation process, using polyatomic molecules having a complicated absorption spectrum such that the isotope shifts are masked, a plurality of laser pulses are used to irradiate a gaseous mixture of molecules including a compound of a desired isotope so as to raise the molecules thereof to higher vibrational energy levels which are substantially unpopulated thermally. The laser pulses have slightly different wavelengths corresponding to respective specific rotational lines of specific vibrational level transitions of molecules containing the desired isotope.