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Keywords:

  • G-particle-hole matrix;
  • reduced density matrix;
  • hypervirial of the G-particle-hole matrix;
  • excited states;
  • ionization potential

Abstract

Recently, through the use of one-electron excitation operators, the set of low-lying excited states of several electronic systems was obtained within the framework of the Hermitian Operator method combined with the G-particle-hole Hypervirial equation method [Valdemoro et al., J. Math. Chem. 2012, 50, 492]. The main aim of this article is to extend our study by including higher-order excitations as well as extended ionization and electron affinity operators. Several examples show the convenience of this extension to improve the accuracy of the results in some relevant cases. Through the use of geminal excitations, the algebra of the formal derivations is considerably simplified. © 2012 Wiley Periodicals, Inc.