Pressure dependence of the electron density in solid iodine by the maximum-entropy method

Abstract

A direct observation of the electron density of solid iodine has been attempted in order to study the electron-density delocalization process due to pressure-induced metallization. A high-accuracy x-ray powder diffraction measurement was carried out with a diamond anvil cell and an imaging plate on a synchrotron-radiation source. The maximum entropy method was employed to analyze the data and to obtain electron-density maps under pressures up to 20 GPa. The electron density between adjacent iodine molecules has been shown to gradually increase with increasing pressure; also, a two-dimensional network is formed at a density level of 0.2 e/ų at around 16 GPa.

Key Words:

• Iodine
• MEM
• high pressure
• metallization
• molecular dissociation
• x-ray