Infrared and ultraviolet absorption spectra of PO and HPO isolated in an argon matrix

Abstract

Upon vacuum ultraviolet photolysis of Ar:PH 3:N 2O deposits at 14 K, PO is formed in sufficient concentration for observation of its vibrational fundamental absorption and of bands associated with three of its electronic transitions, and HPO is formed in sufficient concentration for the identification of both of its ground-state stretching fundamental absorptions. The infrared identifications are supported by studies of the products of the codeposition at 14 K of an Ar:PH 3 sample with an Ar:O 2 sample that had been passed through a microwave discharge. The matrix observations support the assignment of the B 2 Σ +-X 2 Π band system of PO as a valence transition. Detailed isotopic substitution studies have confirmed the assignment of the PH stretching fundamental of ground-state HPO near 2100 cm −1, implying a relatively weak and long PH bond. A four-constant valence force potential has been derived for HPO. Tentative infrared identifications of PO stretching absorptions of PO 2 and (PO) 2 are suggested.