Integrating complete bond dissociation in Class II force fields

Abstract

Predicting the physical and mechanical properties of organic materials from purely chemical understandings remains a significant challenge due to the limitations of conventional force fields in molecular dynamics (MD). In this work, we present a novel reformulation of Class II force fields that integrates Morse bond potentials with newly derived cross-term interactions, explicitly capturing complete bond dissociation while maintaining computational efficiency. This reformulated functional form combines the stability of fixed-bond models with the reactive capabilities of bond-breaking force fields, achieving accurate and robust MD predictions across crystalline, semi-crystalline, and amorphous organic systems. Extensive benchmarking confirms its predictive accuracy and speed, enabling high-throughput structure–property mapping for integrated computational materials engineering. Reparameterization methods have been implemented in the LUNAR software, which provides a user-friendly interface for rapid MD model development and accelerates materials discovery for composite applications.