H₂-AgCl: a spectroscopic study of a dihydrogen complex.

H2-AgCl has been observed on a Fourier transform microwave spectrometer equipped with laser ablation source and determined to be a dihydrogen complex. Transitions up to J = 3-2 have been measured and analyzed for four isotopologues of the complex containing ortho and para H2. The ortho and para spin states have been included in one fit, a deviation from the typical H2 complex. Rotational constants B and C, centrifugal distortion constants Δ(J) and Δ(JK), nuclear electric quadrupole coupling constants χ(aa), χ(bb), and χ(cc) for (35)Cl and (37)Cl have been fit for both spin states while nuclear spin-nuclear spin constants D(aa), D(bb), and D(cc), and nuclear spin-rotation constant C(aa) have been reported for the ortho spin state. Quantum chemical calculations predict a strong bonding interaction and the strength of the complex has been related to reported χ(aa) and Δ(J) values amongst a host of comparable species, including the AgCl monomer itself. Bond lengths have been determined for Ag-Cl, Ag-H2 center-of-mass, and H-H and are reported.