Communication: a Jastrow factor coupled cluster theory for weak and strong electron correlation.

Area of Science:

• Quantum chemistry
• Computational physics
• Theoretical chemistry

Background:

• Coupled cluster (CC) theory is a standard for accurate electronic structure calculations.
• Traditional CC methods struggle with strong electron correlation.
• Jastrow factors are known to improve descriptions of electron correlation.

Purpose of the Study:

• To develop a novel quantum chemistry method combining coupled cluster theory and Jastrow factors.
• To accurately describe both weak and strong electron correlation.
• To provide a more accurate and computationally feasible alternative to existing methods.

Main Methods:

• A Jastrow-factor-inspired variant of coupled cluster theory was developed.
• Integration with quantum Monte Carlo (QMC) for variational energy evaluations.
• Utilized an antisymmetric geminal power (AGP) reference state.

Main Results:

• The method accurately describes both weak and strong electron correlation.
• Achieved a nearly exact description of strong electron correlations in N2 bond breaking.
• Demonstrated superior accuracy over traditional CC and complete active space perturbation theory (CASPT2) for HF and H2O bond dissociations.

Conclusions:

• The Jastrow-factor-inspired CC variant offers a powerful approach for challenging electronic correlation problems.
• The method shows promise for accurate simulations of chemical bond breaking.
• Suggests a fundamental link between Jastrow factors and cluster operators in encoding electron correlation.