In adaptive-partitioning quantum-mechanical/molecular-mechanical (AP-QM/MM) simulations, atoms can be reclassified on-the-fly as QM or MM continuously and smoothly. This is beneficial in the modelling of diffusive systems, such as ion transport through membrane across long distances, for which a small mobile QM zone can be centered at the given ion following it wherever it goes. This allows uninterrupted accurate descriptions of the interactions between the ion and its immediate surroundings. Recently, we extended the two-layer AP-QM/MM scheme to a hierarchical multilayer model that features two QM zones and one MM zone (Q1/Q2/MM). The Q1 zone contains the ion of interests and its first solvation shell, which are treated at a high-level QM theory (e.g., <i>ab initio</i> with a large basis set), and the Q2 zone embraces the atoms in medium range, which are modeled at a low-level QM theory (e.g., <i>ab initio</i> with a small basis set or semi-empirical). The new algorithm can be viewed as a generalization of the celebrated ONIOM method for on-the-fly relocated boundaries between different zones. Two distinct approaches are proposed to treat the Q1/Q2 boundary: (i) the permuted AP method based on weighted many-body expansion of the potential and (ii) the interpolated AP method employing alchemical QM calculations with mixed Q1/Q2 Fock and overlap matrixes.

Adaptive-partitioning multilayer methods for accurate and efficient dynamic simulations

Where thousands of chemistry professionals meet to share ideas and advance scientific and technical knowledge. Spring 2023 abstracts, posters, and presentations will launch at the end of March.

ACS Spring 2023

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.