Data-Driven Investigation of Nuclear Quantum Effects in Liquid Organic Systems

Nuclear quantum effects (NQEs) play an important role in a wide range of systems, especially those involving light nuclei and low temperatures. In the most comprehensive NQE study to date, we employ Path Integral Molecular Dynamics (PIMD), classical MD simulations and various statistical methods to investigate the impact of NQEs on the density, thermal expansion coefficient, isothermal compressibility, dielectric constant, and the heat of vaporization of 87 liquid organic systems spanning various functional groups and molecular features. We show that NQEs have a remarkable impact on all macroscopic properties to varying degrees. The data-driven analyses of chemical characteristics indicate that efficient packing of hydrogen atoms and the system sensitivity to changes in ambient conditions are the major factors governing NQEs. We highlight the competing effects of hydrogen bonds and molecular branching in the context of NQEs. Furthermore, subtle changes in the inter- and intramolecular interaction parameters were found to play a significant role in the magnitude of NQEs. We investigate the changes in material properties due to deuteration often employed in experimental procedures and evaluate the effect of force field on accurate modelling of NQEs. Overall, this work provides a deeper understanding of how NQEs are manifested in material properties and can act as a guide to evaluate whether a specific system requires advanced simulation techniques to encapsulate the physics governing its properties.