title: Infrared spectra of mass-selected Mg+-H2 and Mg+-D2 complexes.
abstract: Rotationally resolved infrared spectra of Mg(+)-H(2) and Mg(+)-D(2) are recorded in the H-H (4025-4080 cm(-1)) and D-D (2895-2945 cm(-1)) stretch regions by monitoring Mg(+) photofragments. The nu(HH) and nu(DD) transitions of Mg(+)-H(2) and Mg(+)-D(2) are red-shifted by 106.2 +/- 1.5 and 76.0 +/- 0.1 cm(-1) respectively from the fundamental vibrational transitions of the free H(2) and D(2) molecules. The spectra are consistent with a T-shaped equilibrium structure in which the Mg(+) ion interacts with a slightly perturbed H(2) or D(2) molecule. From the spectroscopic constants, a vibrationally averaged intermolecular separation of 2.716 A (2.687 A) is deduced for the ground state of Mg(+)-H(2) (Mg(+)-D(2)), decreasing by 0.037 A (0.026 A) when the H(2) (D(2)) subunit is vibrationally excited.
authors.affiliation: School of Chemistry, The University of Melbourne, Victoria, 3010, Australia.
authors.forename: Viktoras
authors.initials: V
authors.lastname: Dryza
authors.forename: Berwyck L
authors.initials: BL
authors.lastname: Poad
authors.forename: Evan J
authors.initials: EJ
authors.lastname: Bieske