Rovibrational laser jet-cooled spectroscopy of SF-rare gas complexes in the ν region of SF.

High resolution infrared spectroscopy combining an external cavity quantum cascade laser with a pulsed pin hole supersonic jet is used to investigate small van der Waals (vdW) heteroclusters containing SF6 and rare gas (Rg) atoms in the ν3 region of SF6. In the first step of the analysis, the rovibrational band contours of parallel and perpendicular transitions of 1 : 1 SF6-Rg heterodimers (Rg = Ar, Kr, Xe) are simulated to derive ground and excited state parameters and hence ground state and equilibrium S-Rg distances with a precision better than 0.5 pm.

Conformational landscape of the SF dimer as revealed by high resolution infrared spectroscopy and complexation with rare gas atoms.

Taking advantage of a versatile set-up, combining pulsed pin hole or slit nozzle supersonic expansion with an external cavity quantum cascade laser, the rovibrational absorption spectrum of the SF dimer in the ν mode region has been revisited at high resolution under various experimental conditions in SF:He mixtures. Two new rotationally resolved spectral bands have been identified in the range of the parallel band of the dimer spectrum in addition to that previously reported. Among these three spectral features, two of them are assigned to conformations of the dimer (noted #1 and #2), clearly distinguished from their different S-S interatomic distances, i.