Phase coexistence in Hamiltonian hybrid particle-field theory using a Multi-Gaussian approach

This study introduces an implementation of multiple Gaussian filters within the Hamiltonian hybrid particle field (HhPF) theory, aimed at capturing phase co-existence phenomena in mesoscopic molecular simulations. By employing a linear combination of two Gaussian filters, we demonstrate that the HhPF approach can generate potentials with attractive components similar to Lennard-Jones potentials, which are crucial for modeling phase co-existence. We compare the performance of this multi-Gaussian filter HhPF method with the Multi-Gaussian Core Model (MGCM) in simulating liquid-gas coexistence for a single-bead system across various densities and temperatures. Our results show that the HhPF method effectively captures detailed information on phase co-existence and interfacial phenomena, including micro-configuration transitions and increased interfacial fluctuations at higher temperatures. Notably, the phase boundaries obtained from HhPF simulations align more closely with those of Lennard-Jones systems compared to the MGCM results. This work advances the hybrid particle-field methodology to address phase co-existence without requiring modifications to the equation of state or introducing additional parameters, offering a promising approach for mesoscale molecular simulations of complex systems.