Tunable vacuum ultraviolet laser spectroscopy: excited state dynamics of jet-cooled molecules and van der Waals complexes

Abstract

In this article we review our recent studies on molecular spectroscopy and photodissociation dynamics of small jet-cooled molecules and van der Waals complexes in the vacuum ultraviolet (VUV) wavelength region ( lambda =200-115 nm) performed using tunable, intense, and coherent VUV light, a so-called tunable VUV laser, generated by a two-photon resonance four-wave sum or difference frequency mixing (2PR-4WSM or 2PR-4WDM) scheme in non-linear media of Sr, Mg, Hg, Xe and Kr. We introduce our progress in high-resolution spectroscopy of electronically excited CO, Cl2, HgRg(Rg=Ne, Ar, Kr), XeRg, Xe2 and photodissociation dynamics of NO2 and OCS. We also describe the generation principle and the characteristic features of the tunable VUV laser and the practical procedure for generating the VUV laser for spectroscopic applications. Emphasis is placed on how the combination of the VUV laser and the free jet expansion techniques is promising for the derivation of precise and substantial information regarding the level structure and the dynamical processes characteristic of highly excited molecular species excited in the VUV wavelength region.