Microwave Spectrum, Structure, and Hyperfine Constants of Kr–AgCl: Formation of a Weak Kr–Ag Covalent Bond

Abstract

The pure rotational spectrum of the complex Kr–AgCl has been measured between 8–15 GHz using a cavity pulsed-jet Fourier transform microwave spectrometer. The complex was found to be linear and relatively rigid, with a Kr–Ag bond length of ∼2.641 Å. The Kr–Ag stretching frequency was estimated to be 117 cm−1. Ab initio calculations performed at the MP2 level of theory gave the geometry, vibration frequencies, Kr–Ag bond dissociation energy, and orbital populations. The Kr–Ag bond dissociation energy was estimated to be ∼28 kJ mol−1. The Kr–Ag force constant and dissociation energy are greater than those of Ar–Ag in Ar–AgCl. The chlorine nuclear quadrupole coupling constants show slight changes on complex formation. Ab initio orbital population analysis shows a small shift in σ-electron density from Kr to Ag on complex formation. The combined experimental and ab initio results are consistent with the presence of a weak Kr–Ag covalent bond.