Polarized Crystal-Field Spectra of Micro Particles of the Moon

Polarized crystal-field spectra of individual crystals, polycrystalline aggregates, and fragments of glass from the moon reveal fundamental information on their transition elements. Specifically, the oxidation states and structural coordination of iron and titanium in lunar samples are determined by a refined technique for measuring crystal-field splitting.

The quenched states of iron and titanium in lunar crystals act as fossil indicators of the chemical history of their crystallization. Spectral and other supporting data show that the rocks and soils returned from the Apollo missions have crystallized under extremely reducing conditions, on the order of approximately 10^{-1 3} atm of oxygen. Lunar glasses are also chemically reduced, and the absorptions of iron and titanium cause their green and red colors and influence their albedo properties.

Measurements of the shift with pressure of crystal-field bands of divalent iron in pyroxene suggest that pressure will enhance the properties of thermal transfer by radiation. Thermal radiation could be an efficient mechanism for heat flow in the lunar interior.