Spectroscopic Behaviour of Quasi-One-Dimensional Linear Chains in MgPt(CN)4 · 7 H2O Single Crystals

Abstract

In the direction of the crystallographic c-axis MgPt(CN)4 · 7 H2O has a relatively low Pt-Pt-distance (3.15 Å at 300°K). Thus the optical behaviour shows inter-molecular interactions. Single crystal polarized emission and absorption spectra were measured between 300°K and 5°K. In this temperature range the emission peaks shift to the red by about 1,100 cm-1. This is attributed to a decrease in Pt-Pt-distance. MgPt(CN)4 · 7 H2O undergoes phase transitions at about 166°K and 60°K. To interprete the solid state emission and absorption behaviour the Davydov theory is applied. The two lowest excited bands of electronic origin are assigned to the symmetries Γ2u(κ) and Γ5u(κ) in the double group D′8h·