A SPIN-ADAPTED COUPLED-CLUSTER BASED LINEAR RESPONSE THEORY FOR DOUBLE IONIZATION POTENTIALS

摘要: We developed in this article a spin-adapted formulation of the coupled-cluster based linear response theory (CC-LRT) for computing double-ionization potentials (DIPs), which may be experimentally observed by Auger spectroscopy. CC-LRT is multireference generalization CC where energy differences have no disconnected vacuum (core) diagrams, signifying core-extensivity. For spin-adaptation equations singlet and triplet manifolds, we used Young-Yamanouchi orthogonal spin-eigenfunctions. The orbital version are then automatically generated conjugate projection operators spin functions. illustrated working our procedure confining to space 2h 1p–3h ionized determinants. As numerical application formalism, computed kinetic energies HF H2O. also analyzed nature size-extensivity DIPs showed explicitly that when molecule composed two noninteracting fragments either fragment A or B composite DIP depending on both B, just not sum ionization (IPs) B. This analysis done underscore fact from only core-extensive fully extensive. © 1996 John Wiley & Sons, Inc.