JOYCE3.0: A General Protocol for the Specific Parametrization of Accurate Intramolecular Quantum Mechanically Derived Force Fields

While the intrinsically multiscale nature of most advanced materials necessitates the use of cost-effective computational models based on classical physics, a reliable description of the structure and dynamics of their components often requires a quantum-mechanical treatment. In this work, we present JOYCE3.0, a software package for the parametrization of accurate, quantum-mechanically derived force fields (QMD-FFs). Since its original release, the code has been extensively automated and expanded, with all novel implementations thoroughly discussed. To illustrate its general applicability, QMD-FFs are parametrized for seven benchmark cases, encompassing molecules with diverse structures and properties. These range from exotic stiff scaffolds, flexible polymeric chains, and polyenes of biological interest to transition-metal complexes. On the one hand, JOYCE3.0 FFs consistently outperform available general-purpose descriptions, achieving excellent agreement with higher-level theoretical methods or available experimental validation data. On the other hand, the remarkable accuracy found in the description of the molecular structures extends to electronic excited states, enabling the integration of the JOYCE3.0 QMD-FFs into multilevel protocols aimed at reliably predicting selected properties and spectral line shapes in advanced optoelectronic materials. The high quality of the results─spanning molecular structures, condensed-phase properties, and spectroscopic features─in combination with the enhanced interface with popular quantum-mechanical codes and molecular dynamics engines, as well as its applicability to chemically diverse species, strongly suggests that JOYCE3.0 could play a pivotal role in the rational design of functionalized materials and heterogeneous systems.