Adiabatic Connection Methods Applied to Molecular Crystals

Area of Science:

• Computational Chemistry
• Materials Science
• Quantum Chemistry

Background:

• Adiabatic Connection Models (ACMs) are typically limited to finite systems.
• Accurate calculation of lattice energies in molecular crystals is crucial for materials science.
• Existing methods like Møller-Plesset adiabatic connection (MPAC) formalism need extension for periodic systems.

Purpose of the Study:

• To extend Møller-Plesset adiabatic connection (MPAC) formalism-based ACMs to periodic molecular crystals.
• To evaluate the accuracy of these extended ACMs for computing lattice energies.
• To identify robust ACMs for modeling energetics in extended systems.

Main Methods:

• Extension of ACMs derived from the MPAC formalism to periodic molecular crystals.
• Computation of lattice energies for 19 representative molecular crystal systems.
• Comparison of ACM results with periodic MP2, high-level reference data, and experimental values.

Main Results:

• Tested ACMs demonstrate accuracy comparable to state-of-the-art dispersion-corrected hybrid density functionals.
• The HFAC24 model, a post-Hartree-Fock parameter-free correlation expression, accurately predicts binding and total energies.
• MPAC-based ACMs show accuracy close to correlated wave function methods for molecular crystal energetics.

Conclusions:

• MPAC-based ACMs offer an accurate and transferable framework for molecular crystal energetics.
• These models represent a systematically improvable approach for developing correlation models for extended systems.
• The HFAC24 model is identified as a highly accurate method for energetics in periodic systems.