Accelerating Wave Function Convergence in Interactive Quantum Chemical Reactivity Studies

TL;DR

This paper introduces two extrapolation-based schemes to accelerate SCF convergence in real-time quantum chemistry, significantly reducing computation time during molecular explorations.

Contribution

The paper presents novel SCF acceleration schemes using extrapolation techniques, improving convergence speed in real-time quantum chemical calculations.

Findings

Achieved up to 30% speedup in SCF calculations.

Reduced number of SCF iterations needed for convergence.

Validated on semi-empirical methods PM6 and DFTB3.

Abstract

The inherently high computational cost of iterative self-consistent-field (SCF) methods proves to be a critical issue delaying visual and haptic feedback in real-time quantum chemistry. In this work, we introduce two schemes for SCF acceleration. They provide a guess for the initial density matrix of the SCF procedure generated by extrapolation techniques. SCF optimizations then converge in fewer iterations, which decreases the execution time of the SCF optimization procedure. To benchmark the proposed propagation schemes, we developed a test bed for performing quantum chemical calculations on sequences of molecular structures mimicking real-time quantum chemical explorations. Explorations of a set of six model reactions employing the semi-empirical methods PM6 and DFTB3 in this testing environment showed that the proposed propagation schemes achieved speedups of up to thirty percent as a consequence of a reduced number of SCF iterations.