Assessing Implicit and Explicit Polarizable Solvation Models for Nuclear-Electronic Orbital Systems: Quantum Proton...

Area of Science:

• Computational Chemistry
• Quantum Mechanics
• Chemical Physics

Background:

• Simulating chemical processes necessitates accounting for nuclear quantum effects and solvent interactions.
• The nuclear-electronic orbital (NEO) approach treats nuclei and electrons quantum mechanically.
• Polarizable continuum models (PCM) represent solvent environments.

Purpose of the Study:

• Extend the NEO-PCM approach to include Surface and Simulation of Volume Polarization for Electrostatics (SS(V)PE) and Domain Decomposed Conductor-like Screening Model (ddCOSMO) methods.
• Analyze nuclear polarization and solvation energies across different PCM formalisms.
• Investigate proton polarization in continuum and explicit solvent models.

Main Methods:

• Implementation of NEO-PCM with SS(V)PE and ddCOSMO solvation models.
• Comparison of solvation energies and nuclear polarization using Integral Equation Formalism PCM (IEF-PCM), Conductor PCM (C-PCM), SS(V)PE, and ddCOSMO.
• Analysis of quantized proton polarization in polarizable MB-pol explicit solvent models.

Main Results:

• NEO-PCM calculations with IEF-PCM, SS(V)PE, C-PCM, and ddCOSMO yield similar solvation energies and nuclear polarization.
• Nuclear density remains localized within the molecular cavity, preventing leakage.
• Explicit solvation models capture specific hydrogen-bonding interactions impacting proton polarization, unlike continuum models.

Conclusions:

• The extended NEO-PCM approach provides a computationally practical method for simulating quantum nuclear effects in solution.
• Different continuum solvation models show comparable results for nuclear polarization and energetics.
• Explicit solvent models are crucial for accurately describing phenomena like hydrogen bonding and its effect on quantized nuclei.