Attachment of molecular hydrogen to an isolated boron cation: An infrared and ab initio study

Abstract

Structural properties of the B+-H2 electrostatic complex are investigated through its rotationally resolved infrared spectrum in the H-H stretch region (3905-3975 cm-1). The spectrum, which was obtained by monitoring B+ photofragments while the IR wavelength was scanned, is consistent with the complex having a T-shaped structure and a vibrationally averaged intermolecular separation of 2.26 Å, which decreases by 0.04 Å when the H2 subunit is vibrationally excited. The H-H stretch transition of B+-H2 is red-shifted by 220.6 ± 1.5 cm-1 from that of the free H 2 molecule, much more than for other dihydrogen complexes with comparable binding energies. Properties of B+-H2 and the related Li+-H2, ..