A combined photoelectron-imaging spectroscopic and theoretical investigation on the electronic structure of the VOH anion.

The electronic structure and vibrational spectrum of the VOH anion are explored by combining photoelectron imaging spectroscopy and density functional theoretical (DFT) calculations. The electron affinity (EA) of VOH is determined to be 1.304 ± 0.030 eV from the vibrationally resolved photoelectron spectrum acquired at 1.52 eV (814 nm). The anisotropy parameter () for the EA defined peak is measured to be 1.63 ± 0.10, indicating that it is the 17a' (4s orbital of the vanadium atom) electron attachment leading to the formation of the ground state of the VOH anion. The vibrational fundamentals , , and are obtained for the neutral ground state. Experimental assignments are confirmed by energies from electronic structure calculations and Franck-Condon (FC) spectral simulations. These simulations support assigning the anion ground state as the results obtained from the B3LYP method. In addition, the molecular orbitals and bonding involved in the anionic VOH cluster are also examined based on the present theoretical calculations.