Mapping the Drude polarizable force field onto a multipole and induced dipole model

Abstract

The induced dipole and the classical Drude oscillator represent two major approaches for the explicit inclusion of electronic polarizability into force field-based molecular modeling and simulations. In this work, we explore the equivalency of these two models by comparing condensed phase properties computed using the Drude force field and a multipole and induced dipole (MPID) model. Presented is an approach to map the electrostatic model optimized in the context of the Drude force field onto the MPID model. Condensed phase simulations on water and 15 small model compounds show that without any reparametrization, the MPID model yields properties similar to the Drude force field with both models yielding satisfactory reproduction of a range of experimental values and quantum mechanical data. Our results illustrate that the Drude oscillator model and the point induced dipole model are different representations of essentially the same physical model. However, results indicate the presence of small differences between the use of atomic multipoles and off-center charge sites. Additionally, results on the use of dispersion particle mesh Ewald further support its utility for treating long-range Lennard Jones dispersion contributions in the context of polarizable force fields. The main motivation in demonstrating the transferability of parameters between the Drude and MPID models is that the more than 15 years of development of the Drude polarizable force field can now be used with MPID formalism without the need for dual-thermostat integrators nor self-consistent iterations. This opens up a wide range of new methodological opportunities for polarizable models.

Tinker-HP: a massively parallel molecular dynamics package for multiscale simulations of large complex systems with advanced point dipole polarizable force fields

“…Various method developments, already present in the Tinker community, will be integrated in the next version of the code, keeping in mind the mandatory philosophy to include only well-understood and scalable techniques. The high-performance implementation of additional multipolar polarizable force fields will be performed including the SIBFA 26 (in progress), MPID 96 (multipole and induced dipoles, the mapping of the CHARMM Drude polarizable force field on induced dipoles) and AMOEBA 2 models. Efforts will also be devoted to the porting of the third generation GEM (Gaussian Electrostatic Model) polarizable force field that relies on frozen distributed densities.…”

A Comparison of QM/MM Simulations with and without the Drude Oscillator Model Based on Hydration Free Energies of Simple Solutes

“…Our recent work [ 133 ] analytically showed that significant additional computational costs can be justified in multi-scale free energy simulations, if the sampling method exhibits a higher phase space overlap with the target QM Hamiltonian. Thus, it can be expected that polarizable force fields and, ultimately, quantum-mechanical methods will play an increasing role in free energy calculations [ 134 , 135 , 136 , 137 , 138 , 139 ].…”

An explicit-solvent hybrid QM and MM approach for predicting pKa of small molecules in SAMPL6 challenge

“…In this case, polarizable force fields should in principle provide higher accuracy in our approach as fixed charge force-fields are limited in their ability to account for the change in charges during the course of the simulation. A theoretically-promising method to handle this effect is to use polarizable force fields such as AMOEBA [68] [69] , Drude [70] or a recently formulated multipole and induced dipole (MPID) model [71]. Any of these polarizable models should improve the pKa prediction results of our method, given high quality polarizable force field parameters for general drug-like molecules are available.…”