Interconfigurational absorption and two-photon excitation spectra of hexachloroplatinate(2-) containing crystals

Abstract

Low-temperature absorption and two-photon excitation spectra of complexes containing PtCl{sub 6}{sup 2{minus}} are presented and discussed. One-photon absorption spectra with moderately well resolved vibronic structure were obtained for PtCl{sub 6}{sup 2{minus}} in dilute mixed crystals. The data show that a transition to a low-lying interconfigurational state is located at {approximately} 18,000 cm{sup {minus}1} in the spectral frequency region below the first absorption transition previously assigned by others. This transition cannot be unambiguously assigned. If it corresponds to the same excited state responsible for the PtCl{sub 6}{sup 2{minus}} emission spectrum, this would lead to a partial reassignment of the excited states from that of earlier work. Ligand field calculations consistent with such a reassignment are presented. The two-photon excitation (TPE) spectra of the mixed Cs{sub 2}ZrCl{sub 6}:PtCl{sub 6}{sup 2{minus}} and pure K{sub 2}PtCl{sub 6} (at 77 K), measured with an improved spectrometer, show a noticeable improvement in signal-to-noise ratio compared to the previously reported TPE spectra of K{sub 2}PtCl{sub 6} and are assigned to higher energy d-d transitions.