NEAR-EDGE OPTICAL-ABSORPTION IN LIQUID IODINE UNDER HIGH-PRESSURE

Absorption coefficient measurements near the optical band edge of liqu id iodine along the melting curve up to 1.52 GPa and 683 K are reporte d. An externally heated diamond anvil cell has been used to pressurize the sample. The spectra are dominated in the 4000-12 000 cm(-1) range by exponential tails of the Urbach type with strongly temperature-dep endent slopes and amplitudes. The possibility of connecting the evolut ion of this spectral feature with the conductivity jumps recently obse rved in liquid iodine around 3-4 GPa is discussed.