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Multireference Stochastic Coupled Cluster.

Maria-Andreea Filip1, Charles J C Scott1, Alex J W Thom1

  • 1Department of Chemistry , University of Cambridge , Cambridge , U.K.

Journal of Chemical Theory and Computation
|November 8, 2019
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Summary
This summary is machine-generated.

This study introduces a new stochastic multireference coupled cluster method. It efficiently handles strongly correlated molecules, offering insights into electronic structure calculations.

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Area of Science:

  • Quantum Chemistry
  • Computational Chemistry
  • Electronic Structure Theory

Background:

  • Stochastic coupled cluster methods are powerful for electronic structure calculations.
  • Strongly correlated systems pose significant challenges for traditional methods.
  • Multireference approaches are often necessary but computationally expensive.

Purpose of the Study:

  • To develop a computationally tractable stochastic multireference coupled cluster (MRCC) method.
  • To enable accurate electronic structure calculations for strongly correlated molecular systems.
  • To provide a flexible framework for investigating electronic structure methods.

Main Methods:

  • Modification of the stochastic coupled cluster algorithm to incorporate multiple reference determinants.
  • Treating secondary references as excitations of the primary reference.
  • Adjusting acceptance criteria for selection and spawning of configurations.

Main Results:

  • A simplified stochastic multireference coupled cluster method is presented.
  • The method successfully describes strongly correlated molecular systems.
  • It requires few references and low cluster truncation levels.
  • Demonstrates flexibility in controlling included references and excitors.

Conclusions:

  • The developed stochastic MRCC method is a promising tool for tackling strong correlation.
  • It retains the advantages of single-reference stochastic coupled cluster approaches.
  • Offers valuable insights into the mechanisms of established electronic structure methods.