Local Second-Order Møller-Plesset Theory with a Single Threshold Using Orthogonal Virtual Orbitals: Theory,...

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Theoretical Chemistry

Background:

• Standard electron correlation methods face computational scaling challenges with increasing molecular size.
• Local correlation methods aim to reduce computational cost by systematically discarding negligible contributions.
• An ideal local method requires a single threshold for controlled accuracy, achieving chemically identical results.

Purpose of the Study:

• To develop and implement a local correlation method for second-order Møller-Plesset (MP2) theory.
• To establish a single numerical threshold for controlled approximation of correlation energy.
• To assess the method's performance across various molecular systems and basis sets.

Main Methods:

• Development of a local MP2 theory incorporating a single, adjustable numerical threshold.
• Implementation using shared memory parallelism (OpenMP) with optimized memory demands.
• Testing with thresholds from 10^-5 to 10^-8 and basis sets up to quadruple-ζ on diverse molecules.

Main Results:

• The local MP2 method demonstrates controlled accuracy for correlation energy calculations.
• The parallel implementation achieves approximately 50% efficiency with 16 cores for large jobs.
• Relative energy calculations show guidance for achieving precision at reduced computational cost.

Conclusions:

• The developed local MP2 method offers a computationally efficient approach to accurate correlation energy.
• Threshold selection is crucial, with derivative properties necessitating tighter thresholds for precision.
• This method provides a practical tool for accurate electronic structure calculations on larger systems.