Raman spectrum of β-PtO2: Evidence for the D2h12-to-D4h14 phase transition

Abstract

Raman spectra are obtained from β-${\mathrm{PtO}}_2$ thin films, which were grown on Pt foils using a high-temperature, high-oxygen-pressure technique. Lines are observed at 205, 340, 606, 616, and 743 ${\mathrm{cm}}^{\mathrm{-}1}$, and are assigned to the ${\mathit{A}}_{\mathit{g}}$, ${\mathrm{B}}_{1\mathrm{g}}$,${\mathit{B}}_{2\mathit{g}}$,${\mathit{B}}_{3\mathit{g}}$, and ${\mathit{A}}_{\mathit{g}}$ modes of the ${\mathrm{CaCl}}_{2\mathrm{-}}$type structure, space group ${\mathit{D}}_{2\mathit{h}}^{12}$. Temperature measurements on these lines point to a second-order phase transition to the rutile structure, space group ${\mathit{D}}_{4\mathit{h}}^{14}$, at 1240±40 K.