Mixing laser spectroscopy and mass spectrometry- infrared spectra of metal cation- hydrogen complexes

Abstract

We describe recent experiments in which mass spectrometry and laser spectroscopy are combined to characterize Li+-H2, Na +-H2, B+-H2 and Al +-H2 complexes in the gas-phase. The infrared spectra, which feature full resolution of rotational sub-structures, are recorded by monitoring M+ photofragments as the infrared wavelength is scanned. The spectra deliver detailed information on the way, in which a hydrogen molecule is attached to a metal cation including the intermolecular separation, the force constant for the intermolecular bond and the H-H stretching frequency. The complexes all possess T-shaped equilibrium geometries and display a clear correlation between the length and force constant..