Magnetic Resonance Properties of Some Lunar Material

Abstract

Paramagnetic resonance spectra of Apollo 11 fines and rocks were measured at 9 and 35 gigahertz and at 4°, 80°, and 300°K. At both frequencies the material has an intense absorption at g = 2, with a line width of ∼950 gauss. Fe ions with strong exchange interactions produce this resonance. A comparison of the resonance absorption due to Fe³⁺ showed that the energy of the crystal field interaction was ∼0.1 per centimeter. Mn²⁺ was identified in several samples, and an absorption at g = 1.89 was tentatively attributed to Ti³⁺. The nuclear magnetic resonance spectra of ²⁷Al had a distribution of asymmetry parameters η ranging from 0.25 to 0.75 and had nuclear quadrupole coupling constants e²qQ/h of approximately 3 megahertz.