An effective energy gradient expression for divide-and-conquer second-order Møller-Plesset perturbation theory

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Materials Science

Background:

• Accurate calculation of molecular properties is crucial in chemistry and materials science.
• Second-order Møller-Plesset perturbation (MP2) theory provides a balance of accuracy and computational cost.
• Linear-scaling methods are essential for treating large systems in electronic structure calculations.

Purpose of the Study:

• To develop an efficient and approximate method for the first derivative of the divide-and-conquer (DC) MP2 energy.
• To enable accurate gradient calculations for large molecular systems using MP2 theory.
• To reduce the computational cost associated with MP2 energy derivative calculations.

Main Methods:

• Implementation of a linear-scaling evaluation scheme for the first derivative of the DC-MP2 energy.
• Evaluation of one- and two-body density matrices using the DC approach.
• Solving local Z-vector equations for efficient gradient computation.

Main Results:

• The proposed method provides an effective approximation for the DC-MP2 energy first derivative.
• The scheme successfully calculates gradients by summing masked subsystem matrices.
• Demonstrated effectiveness across diverse systems including peptides, Si surface models, and polyenes.

Conclusions:

• The developed method offers a computationally efficient route to MP2 energy gradients.
• This approach facilitates the study of larger and more complex chemical and material systems.
• The DC-based gradient calculation is a significant advancement for large-scale electronic structure studies.