The covalent interaction between dihydrogen and gold: A rotational spectroscopic study of H2-AuCl

The pure rotational transitions of H-2-AuCl have been measured using a pulsed-jet cavity Fourier transform microwave spectrometer equipped with a laser ablation source. The structure was found to be T-shaped, with the H-H bond interacting with the gold atom. Both Cl-35 and Cl-37 isotopologues have been measured for both ortho and para states of H-2. Rotational constants, quartic centrifugal distortion constants, and nuclear quadrupole coupling constants for gold and chlorine have been determined. The use of the nuclear spin-nuclear spin interaction terms D-aa, D-bb, and D-cc for H-2 were required to fit the ortho state of hydrogen, as well as a nuclear-spin rotation constant C-aa. The values of the nuclear quadrupole coupling constant of gold are chi(aa) = -817.9929(35) MHz, chi(bb) = 504.0(27) MHz, and chi(cc) = 314.0(27). This is large compared to the eQq of AuCl, 9.63 312(13) MHz, which indicates a strong, covalent interaction between gold and dihydrogen. Published by AIP Publishing.