Towards Electronic Structure-Based Ab-Initio Molecular Dynamics Simulations with Hundreds of Millions of Atoms

Abstract

We push the boundaries of electronic structurebased ab-initio molecular dynamics (AIMD) beyond 100 million atoms. This scale is otherwise barely reachable with classical force-field methods or novel neural network and machine learning potentials. We achieve this breakthrough by combining innovations in linear-scaling AIMD, efficient and approximate sparse linear algebra, low and mixed-precision floating-point computation on GPUs, and a compensation scheme for the errors introduced by numerical approximations.The core of our work is the non-orthogonalized local submatrix (NOLSM) method, which scales very favorably to massively parallel computing systems and translates large sparse matrix operations into highly parallel, dense matrix operations that are ideally suited to hardware accelerators. We demonstrate that the NOLSM method, which is at the center point of each AIMD step, is able to achieve a sustained performance of 324 PFLOP/s in mixed FP16/FP32 precision corresponding to an efficiency of 67.7% when running on 1536 NVIDIA A100 GPUs.

Chemistry Dissolved in Ionic Liquids. A Theoretical Perspective

“…8 Traditionally, ionic liquids (and DESs) have been studied computationally mainly from classical molecular dynamics simulations based on force fields. 9−22 Car−Parrinello or Born−Oppenheimer ab initio molecular dynamics (AIMD) simulations 23 based on the explicit description of the electronic structure concerning ionic liquids 24,25 and deep eutectic solvents 8,26−30 also appeared in the literature. Many contributions and clarifications came from static quantum chemical calculations.…”