Electrostatically Embedded Many-Body Expansion for Simulations

Area of Science:

• Computational Chemistry
• Theoretical Chemistry
• Materials Science

Background:

• Accurate calculation of potential energy gradients is crucial for molecular simulations.
• Traditional methods can be computationally expensive for large systems.
• Developing efficient and accurate methods for force calculations is an ongoing challenge.

Purpose of the Study:

• To evaluate the accuracy of the electrostatically embedded many-body (EE-MB) method at two-body (EE-PA) and three-body (EE-3B) levels for calculating potential energy gradients.
• To assess the suitability of EE-MB methods for molecular dynamics simulations.
• To determine the applicability of EE-MB methods with various electronic structure theories and packages.

Main Methods:

• Application of the electrostatically embedded many-body (EE-MB) method, truncated at the two-body (EE-PA) and three-body (EE-3B) levels.
• Calculation of potential energy gradients for a simulation box of 64 water molecules.
• Utilizing the B3LYP density functional with the 6-31+G(d,p) basis set.

Main Results:

• The EE-PA method reproduced the gradient magnitude within 1.0% error.
• The EE-3B method reproduced the gradient magnitude within 0.1% error.
• Both methods demonstrated high accuracy for force calculations, with EE-3B showing superior precision.

Conclusions:

• The EE-MB methods, particularly EE-3B, are highly accurate and efficient for calculating forces in molecular dynamics simulations.
• The parallel nature and broad applicability of EE-MB methods make them versatile for various computational chemistry studies.
• These methods facilitate accurate force calculations across diverse density functional theory and wave function theory approaches.