InterX Inc., Berkeley, CA 94710;
InterX Inc., Berkeley, CA 94710.
Proc Natl Acad Sci U S A. 2018 Sep 4;115(36):8878-8882. doi: 10.1073/pnas.1806064115. Epub 2018 Aug 20.
In many important processes in chemistry, physics, and biology the nuclear degrees of freedom cannot be described using the laws of classical mechanics. At the same time, the vast majority of molecular simulations that employ wide-coverage force fields treat atomic motion classically. In light of the increasing desire for and accelerated development of quantum mechanics (QM)-parameterized interaction models, we reexamine whether the classical treatment is sufficient for a simple but crucial chemical species: alkanes. We show that when using an interaction model or force field in excellent agreement with the "gold standard" QM data, even very basic simulated properties of liquid alkanes, such as densities and heats of vaporization, deviate significantly from experimental values. Inclusion of nuclear quantum effects via techniques that treat nuclear degrees of freedom using the laws of classical mechanics brings the simulated properties much closer to reality.
在化学、物理和生物学的许多重要过程中，核自由度不能用经典力学定律来描述。与此同时，绝大多数采用广泛覆盖力场的分子模拟都将原子运动视为经典运动。鉴于对量子力学（QM）参数化相互作用模型的需求不断增加和加速发展，我们重新审视经典处理是否足以处理一种简单但至关重要的化学物质：烷烃。我们表明，即使在使用与“金标准”QM 数据非常吻合的相互作用模型或力场时，液体烷烃的一些非常基本的模拟性质，如密度和蒸发热，也会与实验值有很大的偏差。通过使用经典力学定律处理核自由度的技术纳入核量子效应，可以使模拟性质更接近现实。
