Gittus Oliver R, Bresme Fernando
Department of Chemistry, Molecular Sciences Research Hub Imperial College, London W12 0BZ, United Kingdom.
J Chem Phys. 2021 Sep 21;155(11):114501. doi: 10.1063/5.0057868.
The widescale importance and rich phenomenology of water continue to motivate the development of computational models. ReaxFF force fields incorporate many characteristics desirable for modeling aqueous systems: molecular flexibility, polarization, and chemical reactivity (bond formation and breaking). However, their ability to model the general properties of water has not been evaluated in detail. We present comprehensive benchmarks of the thermophysical properties of water for two ReaxFF models, the water-2017 and CHON-2017_weak force fields. These include structural, electrostatic, vibrational, thermodynamic, coexistence, and transport properties at ambient conditions (300 K and 0.997 g cm) and along the standard pressure (1 bar) isobar. Overall, CHON-2017_weak predicts more accurate thermophysical properties than the water-2017 force field. Based on our results, we recommend potential avenues for improvement: the dipole moment to quadrupole moment ratio, the self-diffusion coefficient, especially for water-2017, and the gas phase vibrational frequencies with the aim to improve the vibrational properties of liquid water.
水的广泛重要性和丰富现象学持续推动着计算模型的发展。反应力场（ReaxFF）包含了许多模拟水体系所需的特性：分子灵活性、极化以及化学反应性（键的形成与断裂）。然而，其模拟水的一般性质的能力尚未得到详细评估。我们给出了针对两种ReaxFF模型（水-2017和CHON-2017_弱力场）的水的热物理性质的全面基准测试。这些性质包括在环境条件（300 K和0.997 g/cm³）下以及沿标准压力（1 bar）等压线的结构、静电、振动、热力学、共存和传输性质。总体而言，CHON-2017_弱力场预测的热物理性质比水-2017力场更准确。基于我们的结果，我们推荐了潜在的改进途径：偶极矩与四极矩之比、自扩散系数，特别是对于水-2017而言，以及气相振动频率，目的是改善液态水的振动性质。
