Ground and Low‐Lying Excited States of Nickel Monocarbonyl Obtained by Anion Photoelectron Velocity Map Imaging Spectroscopy

Abstract The photodetachment of nickel monocarbonyl anion was investigated with photoelectron velocity map imaging spectroscopy and analyzed using the existing and new theoretical calculations. The photodetachment experiment conducted at three detachment photon energies (i. e. 1064, 532, and 355 nm) revealed a wealth of spectroscopic information about both the ground state and low‐lying excited states of NiCO. Franck‐Condon simulations were performed to assist the spectral assignment of the vibrationally resolved ground‐state transition. The electron affinity of NiCO is measured to be 0.775±0.002 eV. Three stretching vibrational modes were determined to be activated upon photodetachment, with frequencies of 2016±100, 597±10, and 564±10 cm −1 . The higher‐energy electronic transitions were divided into two congested spectral bands, falling in the ranges of 1.8~2.8 and 2.8~3.5 eV, respectively. The current VMI provided valuable benchmark data for the theoretical calculations on the nickel carbonyls.