V 3$d$ charge and orbital states in V$_2$OPO$_4$ probed by x-ray absorption spectroscopy

Abstract

V 3d charge and orbital states in V 2 OPO 4 have been investigated by means of x-ray absorption spectroscopy (XAS). The electronic structure of V 2 OPO 4 is very unique in that the charge transfer between V 2+ and V 3+ in face sharing VO 6 chains provides negative thermal expansion as reported by Pachoud et al. [J. Am. Chem. Soc. 140, 636 (2018).] The near edge region of O 1s XAS