Residual charges on atoms in organic structures: A new algorithm for their calculation

A fast algorithm for the evaluation of residual charges in organic structures is presented. Its validity extends over single and isolated multiple bonds. The model considers only atom connectivities as the topological basis and atom electronegativities and covalent radii as physical characteristics; the use of an iterative procedure and well-defined computational rules ensures self consistency for the method which is tested through the calculation of atomic charges in several molecules and through a comparison of results obtained with other methods. The Fortran 77 source code RESCHA.FOR the PC executable RESCHA.EXE, sample input PROST.MOL, and resulting output PROST.OUT are included on disk.