Metal-to-metal charge transfer transitions - Interpretation of visible-region spectra of the moon and lunar materialsProminent bands in the spectral profiles of Fe-Ti phases in lunar samples have been attributed to charge-transfer transitions between Fe and Ti cations, and a model is presented for calculating charge transfer energies from energy levels computed by the SCF-X(alpha) scattered wave molecular orbital method for isolated MO6 octahedral coordination clusters containing Fe(2+), Fe(3+), Ti(3+), and Ti(4+) cations. The calculated charge transfer energy for the Fe(2+) to Ti(4+) transition correlates well with a measured spectral feature around 0.6 micron in ilmenite, and, since ilmenite is a major constituent of mare basalts and dark-mantling material, the observed darkness and blueness of the regolith in lunar black spots is attributed primarily to this transition. The Ti(3+) to Ti(4+) transition is thought to contribute to some phases.
Document ID
19780062847
Acquisition Source
Legacy CDMS
Document Type
Conference Proceedings
Authors
Loeffler, B. M. (Massachusetts Inst. of Tech. Cambridge, MA, United States)
Burns, R. G. (MIT Cambridge, Mass., United States)
Tossell, J. A. (Maryland, University College Park, Md., United States)