The low-lying electronic states of VO<sub>4</sub> and VO<sub>4</sub><sup>–</sup>: a computational study
Creators: name: Chou, Yung-Ching
Publisher: name: Taylor & Francis
Year: 2022
Subjects: subject: Biochemistry
subject: 29999 Physical Sciences not elsewhere classified
subject: FOS: Physical sciences
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: Ecology
subject: FOS: Biological sciences
subject: 69999 Biological Sciences not elsewhere classified
subject: Inorganic Chemistry

description: Vanadium tetraoxide (VO<sub>4</sub>) has several isomers, and VO<sub>2</sub>(η<sup>2</sup>-O<sub>2</sub>) is the most stable one. The low-lying doublet states of VO<sub>2</sub>(η<sup>2</sup>-O<sub>2</sub>) and low-lying singlet states of VO<sub>2</sub>(η<sup>2</sup>-O<sub>2</sub>)<sup>−</sup> were studied using the SAC-CI theory. The electron detachment energies from the ground electronic state of VO<sub>2</sub>(η<sup>2</sup>-O<sub>2</sub>)<sup>−</sup> to the low-lying doublet states of VO<sub>2</sub>(η<sup>2</sup>-O<sub>2</sub>) were obtained. These electron detachment energies can be compared with the previous experimental photoelectron spectrum of VO<sub>4</sub><sup>−</sup>, and possible candidate states for the unassigned bands were found. The ground electronic states of VO<sub>2</sub>(η<sup>2</sup>-O<sub>2</sub>)/VO<sub>2</sub>(η<sup>2</sup>-O<sub>2</sub>)<sup>−</sup> and seven doublet excited states of VO<sub>2</sub>(η<sup>2</sup>-O<sub>2</sub>) were optimised. The vertical excitation spectra of VO<sub>2</sub>(η<sup>2</sup>-O<sub>2</sub>) and VO<sub>2</sub>(η<sup>2</sup>-O<sub>2</sub>)<sup>−</sup> were calculated. The lowest doublet/quartet states of VO<sub>4</sub> and lowest singlet/triplet states of VO<sub>4</sub><sup>–</sup> were also computed at the BP86/aug-cc-pVTZ level. <b>Highlights</b>VO<sub>2</sub>(η<sup>2</sup>-O<sub>2</sub>) is the most stable isomer of VO<sub>4</sub>. The low-lying electronic states of VO<sub>2</sub>(η<sup>2</sup>-O<sub>2</sub>) and VO<sub>2</sub>(η<sup>2</sup>-O<sub>2</sub>)<sup>−</sup> were calculated using the SAC-CI theory. The unassigned bands in previous photoelectron spectrum of VO<sub>4</sub><sup>–</sup> were assigned, and the main structures of this spectrum can be described by the electron detachments from VO<sub>2</sub>(η<sup>2</sup>-O<sub>2</sub>)<sup>−</sup> to the low-lying doublet states of VO<sub>2</sub>(η<sup>2</sup>-O<sub>2</sub>).The computational results presented in this study were useful for the spectroscopic studies of VO<sub>4</sub>/VO<sub>4</sub><sup>–</sup>. Knowledge obtained in this study would be also helpful in understanding the electronic structures of MO<sub>4</sub>/MO<sub>4</sub><sup>–</sup> (M = Metal). VO<sub>2</sub>(η<sup>2</sup>-O<sub>2</sub>) is the most stable isomer of VO<sub>4</sub>. The low-lying electronic states of VO<sub>2</sub>(η<sup>2</sup>-O<sub>2</sub>) and VO<sub>2</sub>(η<sup>2</sup>-O<sub>2</sub>)<sup>−</sup> were calculated using the SAC-CI theory. The unassigned bands in previous photoelectron spectrum of VO<sub>4</sub><sup>–</sup> were assigned, and the main structures of this spectrum can be described by the electron detachments from VO<sub>2</sub>(η<sup>2</sup>-O<sub>2</sub>)<sup>−</sup> to the low-lying doublet states of VO<sub>2</sub>(η<sup>2</sup>-O<sub>2</sub>). The computational results presented in this study were useful for the spectroscopic studies of VO<sub>4</sub>/VO<sub>4</sub><sup>–</sup>. Knowledge obtained in this study would be also helpful in understanding the electronic structures of MO<sub>4</sub>/MO<sub>4</sub><sup>–</sup> (M = Metal).