CMx charges for SCC-DFTB and some GaN vignettes

Christopher J. Cramer, cramer@pollux.chem.umn.edu, Department of Chemistry and
Supercomputing Institute, University of Minnesota, 207 Pleasant St. SE,
Minneapolis, MN 55455-0431

In the self-consistent charge density functional tight binding method (SCC-DFTB)
the second-order expansion of the DFT energy with respect to probability density
fluctuations is accounted for via pairwise interactions between atomic partial
charges determined in a self-consistent fashion. CMx charges are determined from
an optimized mapping procedure and improve upon Class II charge models. In
addition to a discussion of this technical extension, time will be devoted to
modeling the chemistry of molecular precursors to GaN.