Vibrationally resolved photoelectron imaging of platinum carbonyl anion Pt(CO)n− (n = 1-3): Experiment and theory

Photodetachment of platinum carbonyl anions Pt(CO)(n)(-) (n = 1, 3) had been previously investigated using traditional photoelectron spectroscopy (PES) [G. S. Icking-Konert, H. Handschuh, G. Ganteför, and W. Eberhardt, Phys. Rev. Lett. 76, 1047 (1996); B. Chatterjee, F. A. Akin, C. C. Jarrold, and K. Raghavachari, J. Chem. Phys. 119, 10591 (2003)]. Here, we studied Pt(CO)(n)(-) (n = 1-3) using photoelectron velocity-map imaging method and extensive theoretical calculations. Vibrationally resolved spectra from photoelectron imaging experiments allow determination of the electron affinities of Pt(CO)(n), which are 1.196 ± 0.034, 0.930 ± 0.042, and 1.253 ± 0.032 eV for n = 1, 2, and 3, respectively. Two vibrational progressions are resolved for the ground states of Pt(CO) and Pt(CO)(3), while only one is resolved for that of Pt(CO)(2). The frequencies are determined to be 2089 ± 91 and 581 ± 21 cm(-1) for Pt(CO), 2173 ± 115 cm(-1) for Pt(CO)(2) and 2119 ± 88 and 444 ± 18 cm(-1) for Pt(CO)(3). Results from density functional theory and ab initio calculations agreed well with the experimental observations. The spectra were well reproduced by Franck-Condon fitting on the basis of the optimized geometries and the theoretical frequencies. The well-resolved PES also provided valuable benchmarks for various density functionals (B3LYP, BP86, and PW91PW91) for the platinum carbonyls.