Orbital-Optimized Distinguishable Cluster Theory with Explicit Correlation.

@article{Kats2018OrbitalOptimizedDC,
  title={Orbital-Optimized Distinguishable Cluster Theory with Explicit Correlation.},
  author={Daniel Kats and David P. Tew},
  journal={Journal of chemical theory and computation},
  year={2018},
  volume={15 1},
  pages={
          13-17
        },
  url={https://api.semanticscholar.org/CorpusID:54485300}
}
It is shown that the perturbative approach is applicable even in strongly correlated situations, and it is important in these cases to use Lagrange multipliers together with the amplitudes.
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13 Citations

On the distinguishable cluster approximation for triple excitations.

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It is found that methods derived from the Ansatz beyond the previously known ODC-12 method tend to be less accurate for equilibrium properties and less reliable when attempting to describe H2 dissociation.

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Multi-state local complete active space second-order perturbation theory using pair natural orbitals (PNO-MS-CASPT2).

A multistate complete active space second-order perturbation theory (CASPT2) method is presented, which utilizes domains of pair natural orbitals and projected atomic orbitals for the virtual space…

Explicitly correlated coupled cluster method for accurate treatment of open-shell molecules with hundreds of atoms.

This work presents a near-linear scaling formulation of the explicitly correlated coupled-cluster singles and doubles with the perturbative triples method [CCSD(T)F12¯] for high-spin states of open-shell species using the domain local pair-natural orbitals (DLPNO) framework.

FCIQMC-Tailored Distinguishable Cluster Approach

It is demonstrated that the new method is more accurate than the corresponding tailored coupled cluster and the pure distinguishable cluster methods and an F12 correction for tailored methods and FCIQMC is introduced, which drastically improves the basis set convergence.

Cumulants as the variables of density cumulant theory: A path to Hermitian triples.

This new Ansatz solves problems identified in the previous unitary coupled cluster Ansatz for density cumulant theory: the theory is now free of near-zero denominators between occupied and virtual blocks, can correctly describe the dissociation of H2, and is rigorously size-extensive.

Variational coupled cluster for ground and excited states.

The structure of the energy landscape of variational CC is explored and it is compared with its (projected) traditional version in the case where the excitation operator is restricted to paired double excitations (pCCD).

FCIQMC-Tailored Distinguishable Cluster Approach: Open-Shell Systems

A recently proposed tailored approach based on the distinguishable cluster method and the stochastic FCI solver, FCIQMC [J. Chem. Theory Comput. 2020, 16, 5621], is extended to open-shell molecular…

33 References

Relaxing Constrained Amplitudes: Improved F12 Treatments of Orbital Optimization and Core-Valence Correlation Energies.

A Lagrangian correction is presented that eliminates the systematic basis set error of the posthoc F12 treatment in orbital optimized methods and can be used to relax the F12 amplitudes and significantly reduce the sensitivity of the core-valence correlation energies to the exponent of the correlation factor.

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The replacement of single excitations by orbital transformations in coupled-pair functionals derived from a single double configuration interaction approach is discussed. It is demonstrated that this…

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It is shown that the usual F12-type explicitly correlated approaches are applicable to distinguishable-clusters theory with single and double excitations, and the results show a significant improvement compared to coupled-cluster theory with singles and doubles for closed and open-shell systems.

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The distinguishable cluster approximation proposed in Paper I [D. Kats and F. R. Manby, J. Chem. Phys. 139, 021102 (2013)] has shown intriguing abilities to accurately describe potential energy…

Improving the distinguishable cluster results: spin-component scaling

ABSTRACT The spin-component scaling is employed in the energy evaluation to improve the distinguishable cluster approach. SCS-DCSD reaction energies reproduce reference values with a…

Explicitly correlated wave functions: summary and perspective

We summarize explicitly correlated electronic structure theory in perspective of future work in the field. Earlier stages of approaches with different Ansätze in physics and chemistry are described.…

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A new method that accurately describes strongly correlated states and captures dynamical correlation is presented, called the distinguishable cluster approximation, which smoothly dissociates difficult cases such as the nitrogen molecule, with the modest N^6 computational cost of CCSD.

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