Formalisms and Applications of Charge Density Analysis for the 21st Century. Edwin D. Stevens, Department of Chemistry, University of New Orleans, New Orleans, LA 70148

Some speculation on future trends in formalisms and applications of charge density analysis will be presented. Topics will include quantum crystallography refinement methods, calculations on molecular systems using modern density functional theory methods, and new formalisms and applications designed to take advantage of rapid data collection methods. Results will be presented of recent work using a quantum constrained refinement in which an experimental wavefunction and total energy of the azide ion were obtained from x-ray data. Results of a comparison between charge density distributions of Rh(PPh3)2(CO)(NCO) obtained from low temperature x-ray data collected with a CCD detector and distributions calculated using DFT theory will also be presented.