Crossed laser and molecular beam studies of mixed alkali dimer: preparation, perturbation and predissociation

Abstract

Recent developments in tunable lasers and molecular beams have enabled a major refinement in the study of molecular properties. For example, the supersonic nozzle beam preparation technique has brought the spectral resolution of measurements of homonuclear and heteronuclear alkali dimers in our laboratory down to 0.001 cm^–1(= 30 MHz). Apart from classical applications, such as accurate determination of vibrational and rotational constants, dimer concentrations and internal distributions, “selectively detected laser-induced fluorescence (SDLIF)” spectroscopy opens up possibilities of studying new fundamental properties of these molecules. Thus, studies of individual rotational levels have revealed that predissociation phenomena are much more common than was earlier believed. In addition to an increased knowledge of basic molecular properties, these phenomena have important applications, such as the accurate determination of dissociation energies and molecular formation rates. It is also shown that crossed laser and molecular beam studies are a powerful tool for investigating perturbation effects.