Pressure-induced electron transfer in quasi-molecular solids
Department of Physics and Astronomy, The University of Edinburgh,
Mayfield Road, Edinburgh EH9 3JZ, Scotland, UK
Accepted: 12 August 1996
A combination of Raman scattering and synchrotron X-ray powder diffraction on Group-V metal triiodides (, ) has revealed a continuous isostructural transition from a molecular solid to a two-dimensional layered crystal under high pressure. The loss of molecular identity proceeds by gradual pressure-induced electron transfer from intramolecular to intermolecular bonds and suppression of sp3 hybridisation. Initial pressure increase has the effect of destroying molecular units while continued compression enhances intralayer cohesion. These two effects give rise to a non-monotonic pressure variation of the X-I bond-stretching frequency.
PACS: 61.10.-i – X-ray diffraction and scattering / 68.65.+g – Layer structures: multilayers, and superlattices (growth, structure, and nonelectronic properties) / 78.30.-j – Infrared and Raman spectra and scattering
© EDP Sciences, 1996