The resonance Raman spectra of MoSe42− and WSe42−. Anharmonicity constants X11 of MoS42−, MoSe42−, WSe42− and similar ions

Abstract Resonance Raman spectra of MoS 4 2− , MoSe 4 2− and WSe 4 2− are reported. The anharmonicity constant X 11 was found to be approximately zero. A comparison of these seleno- and thioanions with similar oxoanions indicates that these ions having ν 1 at lower frequency are less anharmonic.