Laser Vibrational Spectroscopy of Transient, Weakly Bound, and Reactive Molecules

Abstract

Using laser spectroscopic techniques, namely Stimulated Emission Spectroscopy (SES) and Stark Level Crossing Spectroscopy, in combination with molecular beam techniques, we can now study vibrational levels with energies from zero to tens-of-thousands wavenumbers with sub-Doppler resolution and single rotational level selectivity. Molecular species with concentrations as low as 10−4 Torr can be studied. Low-frequency intermolecular van der Waals vibrational levels in a weakly bound complex can be directly observed for the elucidation of intermolecular forces. Short-lived radicals can be studied at high vibrational excitation. The dissociation behavior of a molecule with vibrational energy higher than the dissociation barrier can be examined with single vibrational quantum state resolution.