Quantum Monte Carlo with Jastrow-valence-bond wave functions.

Area of Science:

• Computational chemistry
• Quantum mechanics
• Materials science

Background:

• Accurate modeling of electron correlation is crucial for predicting molecular properties.
• Traditional wave function methods often struggle with computational cost for larger systems.
• Valence bond methods offer a chemically intuitive approach to electron correlation.

Purpose of the Study:

• To investigate the efficacy of Jastrow-valence-bond wave functions in quantum Monte Carlo calculations.
• To assess the performance of valence bond self-consistent-field and breathing-orbital valence bond wave functions.
• To compute and analyze the equilibrium well depths of C2, N2, O2, and F2.

Main Methods:

• Utilized variational Monte Carlo and diffusion Monte Carlo methods.
• Employed Jastrow-valence-bond wave functions incorporating localized active orbitals.
• Calculated equilibrium well depths for four diatomic molecules.

Main Results:

• Jastrow-valence-bond wave functions demonstrated capability in describing static and dynamic electron correlations.
• Accurate well depths were obtained for C2, N2, O2, and F2.
• The wave functions are compact and designed based on chemical principles.

Conclusions:

• Developed valence bond wave functions provide a promising route for accurate quantum Monte Carlo simulations.
• These methods offer a balance between accuracy and computational efficiency.
• Systematic improvement is possible through the inclusion of additional valence bond structures.