Efficient generation of flexible-monomer intermolecular potential energy surfaces

Area of Science:

• Computational Chemistry
• Theoretical Chemistry
• Molecular Interactions

Background:

• Accurate intermolecular potentials are crucial for molecular simulations.
• Existing methods often struggle to efficiently incorporate monomer flexibility.
• Computational cost increases significantly with the inclusion of internal degrees of freedom.

Purpose of the Study:

• To develop a computationally inexpensive method for generating flexible-monomer intermolecular potentials.
• To extend rigid-monomer potentials to account for monomer non-rigidity.
• To assess the accuracy of the new method in capturing non-rigidity effects.

Main Methods:

• The proposed method utilizes symmetry-adapted perturbation theory.
• It extends rigid-monomer potentials to flexible-monomer potentials.
• Non-rigidity effects are incorporated via density-overlap integrals and asymptotic expansion coefficients.

Main Results:

• The method achieves negligible computational overhead compared to full-dimensional calculations.
• It successfully recovers a significant portion of non-rigidity effects for a model system.
• Results for the Ar-HF system validate the approach's effectiveness.

Conclusions:

• The new method provides an efficient and accurate way to generate flexible-monomer intermolecular potentials.
• This approach offers a significant advantage for large-scale molecular simulations requiring flexibility.
• It paves the way for more realistic modeling of molecular systems with internal degrees of freedom.