Infrared spectroscopic and theoretical studies on the formation of Au2NO- and Au(n)NO (n = 2-5) in solid argon

Laser-ablated gold atoms have been codeposited at 4 K with nitric oxide in excess argon and the low temperature reactions of Au with NO in solid argon have been studied using infrared spectroscopy. The reaction products Au(2)NO(-), Au(2)NO, Au(3)NO, Au(4)NO, and Au(5)NO are formed in the present experiments and characterized on the basis of isotopic shifts, mixed isotope splitting patterns, stepwise annealing, the change in reagent concentration and laser energy, and comparison with theoretical predictions. Density functional theory calculations have been performed on these systems to identify possible reaction products. The agreement between the experimental and calculated vibrational frequencies, relative absorption intensities, and isotopic shifts supports the identification of these molecules based on the matrix infrared spectra. Plausible reaction pathways have been proposed for the formation of these molecules.