Michael Hehenberger

Transition operators for molecular ΔESCF calculations: Ionization in water and furan

Abstract Ab initio calculations of binding energies with a transition operator method are performed. They are demonstrated to include relaxation, which is essential for the prediction of deep-hole chemical shifts.

A dynamical damping scheme for converging molecular scf calculations

Abstract A new method for achieving or speeding up SCF convergence in molecular ab initio calculations is presented. Mullikenś gross populations are calculated in each cycle and extrapolated in order to derive an optimal damping factor for the density matrix in the basis of atomic orbitals. The damping factor is taken as the average of the calculated atomic damping factors. weighted by the respective numbers of basis functions per atom. In the case of a symmetry-adapted basis, the damping factors are calculated separately for each irreducible representation. Applications to the molecules CuCl42− and CO demonstrate the superiority of this “dynamical damping scheme” as compared to conventional “static” methods.