Multireference Stochastic Coupled Cluster

Abstract

We describe a modification of the stochastic coupled cluster algorithm that allows the use of multiple reference determinants. By considering the secondary references as excitations of the primary reference and using them to change the acceptance criteria for selection and spawning, we obtain a simple form of stochastic multireference coupled cluster which preserves the appealing aspects of the single reference approach. The method is able to successfully describe strongly correlated molecular systems using few references and low cluster truncation levels, showing promise as a tool to tackle strong correlation in more general systems. Moreover, it allows simple and comprehensive control of the included references and excitors thereof, and this flexibility can be taken advantage of to gain insight into some of the inner workings of established electronic structure methods.

arXiv comment18 pages, 13 figures. The latest version corrects some typographical errors in the operators on p. 3-4

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Cited by in corpus (5)

• The Shape of Full Configuration Interaction to Come
• A hybrid stochastic configuration interaction-coupled cluster approach for multireference systems
• Exploration of interlacing and avoided crossings in a manifold of potential energy curves by a Unitary Group Adapted State Specific Multi-Reference Perturbation Theory (UGA-SSMRPT)
• Rapidly convergent quantum Monte Carlo using a Chebyshev projector
• Stochastic evaluation of four-component relativistic second-order many-body perturbation energies: A potentially quadratic-scaling correlation method