Theoretical calculations of photoelectron spectrum of (Au–CO2)− anion

Abstract Photoelectron spectra of the (Au–CO 2 ) − anion complex have been calculated using both quantum path-integral and classical molecular dynamics methods to interpret the experimentally measured spectrum, showing a double-peak feature corresponding to two different anion configurations of Au·CO 2 − and Au − ·CO 2 . The anionic potential energy surfaces have been developed on the basis of density-functional theory calculation results obtained with several different levels. We found that the calculated photoelectron spectra significantly depend on the relative energies of these two isomers and the isomerization barrier heights. Nuclear quantum effects are playing important roles for obtaining reliable spectra through vibrational quantization. The present calculations also suggest that the photoelectron spectrum intensity around the overlap region of the two anion peaks can provide a fingerprint of the Au·CO 2 −  ↔ Au − ·CO 2 reaction.