CHELP-SVD is now available at the Bryn Mawr College gopher (gopher.brynmawr.edu). Look under Academic Departments/Chemistry/CHELP Information regarding CHELP-SVD Authors: Michelle Miller Francl Lisa Emily Chirlian Contact Information: Department of Chemistry Bryn Mawr College 101 N. Merion Avenue Bryn Mawr, PA 19010-2899 610 526 5108 mfrancl@cc.brynmawr.edu lchirlia@cc.brynmawr.edu Copyright notice: ****IMPORTANT**** CHELP-SVD is a copyrighted program. No part of it may be used in commercial software without the express consent of the authors. Permission is granted to copy and distribute this software under the constraints expressed above, provided this copyright notice is attached. Users are asked to reference the article describing CHELP-SVD when describing work done with it or modified versions thereof. ****IMPORTANT**** Description: This code is a modification of CHELP (Chirlian, L.E.; Francl, M.M. QCPE 1987, 7, 39). CHELP-SVD will find potential derived charges for molecules using as input the molecular wavefunction. CHELP-SVD will do a preliminary fit, determine the rank of the least squares matrix for the fit, select an appropriate subset of atoms to which charges can be assigned based on that rank estimate and then refit the selected set of charges. A description of the methods incorporated into CHELP-SVD can be found in "Charges Fit to Electrostatic Potentials II: Can Atomic Charges be Unambiguously Fit to Electrostatic Potentials?" by C. Carey , L.E. Chirlian, D. M. Gange and M.M. Francl which has been submitted to the Journal of Computational Chemistry and "Charges Fit to Electrostatic Potentials", L.E. Chirlian and M.M. Francl, J. Comp. Chem. 8, 894 (1987). An abstract of the most recent paper is available on this gopher.