Efficient Monte Carlo Simulation of Faceted Nanoparticles Interacting with Analytical Potentials

Faceted nanoparticles (NPs) can self-assemble into complex structures with tunable optical, plasmonic, and catalytic properties, making them useful building blocks for soft materials. To understand their self-assembly, most studies either model them as hard particles or approximate their energetic interactions inaccurately using coarse-grained models due to computational reasons. To this end, we recently developed an analytical potential [1] that can efficiently yet accurately capture van der Waals interactions. In this work, we incorporate this potential into a virtual-move Monte Carlo framework [2], enabling efficient sampling. Compared to coarse-grained models, which fail to reproduce atomistic morphologies, our approach simulates NP assembly orders of magnitude faster while closely matching atomistic results. We also examined phase behavior of faceted NPs with various shapes under weak and strong interactions, presenting one of the first studies of phase diagrams for attractive faceted NPs. Our results show that attractive interactions enhance ordering of NPs by shifting the isotropic-to-semiordered transition to lower volume fractions, while the semiordered-to-crystalline transition remains mainly entropy-driven. These findings highlight the importance of enthalpic effects and the advantage of our framework over hard-particle potentials.

[1] Lee, B.H.; Arya, G. Nanoscale Horiz. 2020, 5, 1628–1642.

[2] Whitelam, S.; Geissler, P.L. J. Chem. Phys. 2007, 127, 154101.