AI Article Synopsis

  • The Fock space multireference coupled-cluster (FSMRCC) method is designed to efficiently analyze the electronic structure in systems with nearly degenerate energy levels.
  • Developing a linear response framework for FSMRCC has been challenging due to the complexities arising from multiple roots in the effective Hamiltonian.
  • The paper introduces a new FSMRCC approach that allows for the calculation of analytic response properties like dipole moments and polarizabilities for molecules such as H2O, O3, and CH+, while also discussing aspects of spin adaptations in the method.

Article Abstract

Fock space multireference coupled-cluster (FSMRCC) method emerged as an efficient tool to describe the electronic structure of nearly degenerate cases. Development of linear response has been one of the challenging problems in FSMRCC due to the multiple-root nature of the effective Hamiltonian. A response from any of the roots would span the space for getting the properties. Hence, all roots perturbed by the external field would proliferate the excited states. We recently developed the FSMRCC method for the efficient evaluation of analytic response properties using a constrained variation approach. In this paper, we present analytic dipole moments and polarizabilities of H(2)O, O(3), and CH(+) molecules in low-lying excited states along with brief discussion of singlet triplet decoupling of (1,1) sector of FSMRCC resulting from spin adaptation.

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http://dx.doi.org/10.1063/1.3167796DOI Listing

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