Interaction of intense beams of highly vibrationally excited molecules with molecules (clusters) condensed on a cold surface

The interaction of intense beams of SF₆ and CF₃I molecules, excited by powerful IR laser radiation to high vibrational states (0.3 eV ≤ E _vib ≤ 2.0 eV), with molecules (clusters) condensed on a cold surface (T _s ≈ 80–85 K) has been studied. The probability that the excited and unexcited molecules are reflected from the cold metal surface covered by condensed molecules (clusters), as well as the probability that such excited and unexcited molecules are transmitted through a cooled multichannel metal plate and a converging cone oriented at an angle relative to the molecular beam axis, has been determined. Expressions for these probabilities of reflection and transmission as functions of the angle of incidence and the parameters of the exciting laser radiation and the molecular beam are obtained. It is shown that highly vibrationally excited molecules are reflected from the surface and transmitted through the plates and cones with a much higher probability than unexcited molecules. The results suggest that this phenomenon can be used for the separation of molecules in a beam with respect to isotope (or atomic) composition.