Implementation of Geometry-Dependent Charge Flux into the Polarizable AMOEBA+ Potential

Abstract

Molecular dynamics (MD) simulations employing classical force fields (FFs) have been widely used to model molecular systems. The important ingredient of the current FFs, atomic charge, remains fixed during MD simulations despite the atomic environment or local geometry changes. This approximation hinders the transferability of the potential being used in multiple phases. Here we implement a geometry dependent charge flux (GDCF) model into the multipole-based AMOEBA+ polarizable potential. The CF in the current work explicitly depends on the local geometry (bond and angle) of the molecule. To our knowledge, this is the first study that derives energy and force expressions due to GDCF in a multipole-based polarizable FF framework. Due to the inclusion of GDCF, the AMOEBA+ water model is noticeably improved in terms of describing the monomer properties, cluster binding/interaction energy and a variety of liquid properties, including the infrared spectra that previous flexible water models were not able to capture. File list (2) download file view on ChemRxiv AMOEBA+CF_Manuscript.pdf (1.22 MiB) download file view on ChemRxiv AMOEBA+CF_SI.pdf (0.91 MiB)

Development of the Quantum Inspired SIBFA Many-Body Polarizable Force Field: Enabling Condensed Phase Molecular Dynamics Simulations

“…As mentioned above, it has been shown that the choice of a larger angle value is required to accurately represent the geometry fluctuation of water in condensed phase. 35 The present model does not rely on charge flux as for AMOEBA+ 67 in order to test the intrinsic capabilities of the native SIBFA components. Moreover, the SIBFA21 water model is flexible leading to a good agreement of binding energy for the Smith dimers.…”

“…The refinement of a polarizable water model is considered an essential validation prerequisite for any polFF destined to perform MD simulations on large chemical and biochemical complexes. [8][9][10][11][12][13][14] The description of water with a polFF is challenging 15 as it requires a detailed understanding of its intermolecular interactions, and is also a marker of its predictive ability. Several polarizable water models were recently reported (not all suitable for MD simulations), grounded either on Energy Decomposition Analysis (EDA) methods, such as the MB-UCB-MDQ 16 water model using the Absolutely Delocalized Molecular Orbital (ALMO), 17 or grounded on Symmetry Adapted Perturbation Theory (SAPT) 18,19 such as EFP (Effective Fragment Potential), 20,21 the polarizable SAPT-5, 22 MB-POL, 23 Distributed Point Polarizable model (DPP), 24 Gaussian Electrostatic Model (GEM), 14,[25][26][27] Hydrogen-like Intermolecular Polarizable POtential (HIPPO 28 ), Derived Intermolecular Force-Field (DIFF), 29 AMOEBA+ (Atomic Multipole Optimized Energetics for Biomolecular Simulation +), 11,12 and others.…”

Testing the Limitations of MD-based Local Electric Fields Using the Vibrational Stark Effect in Solution: Penicillin G as a Test Case

“…It is difficult to pinpoint whether improvements of geometric or electrostatic properties are necessary for a more reliable description of hydration electrostatics around the polar and charged functional groups of PenG (see SI section 9 for brief comparison of MD and DFT-based electric field estimations). As such, it will be interesting to test in future studies whether the current improvements of polarizable MD models such as AMOEBA+, 86 AMOEBA+cf, 87 aniso-AMOEBA, 88 or the MB-pol many body potential 89 will provide more accurate descriptions of solvation electrostatics for solutes of diverse structures and charge distributions, or if ab initio MD methods must be employed. In addition to such advances, we highlight the necessity of benchmarking force fields against molecular observables, such as the VSE, to account for the highly heterogeneous behavior of water when interacting with a charged functional group, which is often undervalued when focusing on bulk averaged properties.…”

DL_FFLUX: a parallel, quantum chemical topology force field

“…polarisability). We note that there are more recent, improved water potentials other than SPC that include polarisation in various ways 53,54 .…”