Pressure-induced reverse Peierls and Peierls instabilities in halogen-bridged binuclear metal complexes

Abstract

The pressure-induced reverse Peierls and Peierls instabilities which coexist in halogen (X)-bridged binuclear platinum complexes R 4[Pt 2(P 2O 5H 2) 4X]· nH 2O are interpreted by finite-temperature Hartree–Fock calculations. An applied pressure replaces the initial charge-polarization state by a charge-density-wave state at high temperatures, whereas the charge-density-wave state oppositely declines with increasing pressure at low temperatures. These contrasting observations turn out to be ascribed to pressure-induced simultaneous increases of the interdimer electron transfer and Coulomb repulsion. The obtained theoretical scenario could be proved by high-pressure experiments.