Infrared Photodissociation Spectroscopic and Theoretical Study of [Co(CO2)(n)](+) Clusters

The mass-selected infrared photodissociation (IRPD) spectroscopy was utilized to investigate the interactions of cationic cobalt with carbon dioxide molecules. Quantum chemical calculations were performed on the [Co(CO2)(n)](+) clusters to identify the structures of the low-lying isomers and to assign the observed spectral features. All the [Co(CO2)(n)](+) (n=2-6) clusters studied here show resonances near the CO2 asymmetric stretch of free CO2 molecule. Experimental and calculated results indicate that the CO2 molecules are weakly bound to the Co+ cations in an end-on configuration via a charge-quadrupole electrostatic interaction. The present IRPD spectra of [Co(CO2)(n)](+) clusters have been compared to those of Ar-tagged species ([Co(CO2)(n)](+)-Ar), which would provide insights into the tagging effect of rare gas on the weakly-bounded clusters