ESR of VO in Argon Matrix at 4°K; Establishment of Its Electronic Ground State

Abstract

ESR spectrum of VO isolated in argon matrix at 4°K was obtained. The analysis of the spectrum led to the unequivocal assignment of its electronic ground state as ${}^4\Sigma$ arising from the configuration ${\sigma }^2{\pi }^4{\sigma }^1{\delta }^2$ . Due to the extremely large zero‐field fine‐structure splitting, the entire spectrum was found to be compatible with the effective spin Hamiltonian of the form $$\mathfrak{H}{\mathrm{\hspace{0.17em}=\hspace{0.17em}g}}_{\Vert }{\mathrm{\beta H}}_z{S}_z{\text{\hspace{0.17em}+\hspace{0.17em}2g}}_{\perp }{\mathrm{\beta (H}}_x{S}_x{\mathrm{\hspace{0.17em}+\hspace{0.17em}H}}_y{S}_y{\mathrm{)\hspace{0.17em}+\hspace{0.17em}A}}_{\Vert }{I}_z{S}_z{\text{\hspace{0.17em}+\hspace{0.17em}2A}}_{\perp }{\mathrm{(I}}_x{S}_x{\mathrm{\hspace{0.17em}+\hspace{0.17em}I}}_y{S}_y\mathrm{),}$$ with the following parameters: $g_{\Vert }{\text{\hspace{0.17em}=\hspace{0.17em}2.0023\hspace{0.17em}±\hspace{0.17em}0.001, g}}_{\perp }{\text{\hspace{0.17em}=\hspace{0.17em}1.9804\hspace{0.17em}±\hspace{0.17em}0.001, A}}_{\Vert }\text{\hspace{0.17em}=\hspace{0.17em}714.7\hspace{0.17em}±\hspace{0.17em}0.5}\mathrm{MHz}$ , and $A_{\perp }\text{\hspace{0.17em}=\hspace{0.17em}837.1\hspace{0.17em}±\hspace{0.17em}0.5}\mathrm{MHz}$ .