IR multiphoton excitation of SF6 molecules subliming from the surface of (CO2)N nanoparticles in a cluster beam

This work examines IR multiphoton excitation of SF6 molecules subliming from the surface of (CO2)N van der Waals clusters (nanoparticles) in a cluster beam (the number of monomers per cluster, N≥102). The SF6 molecules are captured by clusters when a cluster beam intersects a molecular beam and sublime from the cluster surface after a certain time, carrying information about the velocity and temperature (internal energy) of the clusters. The multiphoton absorption spectra of the SF6 molecules subliming from the cluster surface are markedly narrower than those of the SF6 molecules in the parent, gas-dynamically cooled molecular beam, indicating that the vibrational temperature of the molecules subliming from the cluster surface is lower. Therefore, the proposed technique can be used to produce strongly vibrationally cooled molecules, which are of interest for a number of applications, in particular for achieving high-selectivity IR multiphoton excitation and isotopically selective dissociation of molecules. (nonlinear optical phenomena)