Investigating the energetic and entropic components of effective potentials across a glass transition
Investigating the energetic and entropic components of effective potentials across a glass transition
复制标题
研究玻璃化转变过程中有效势的能量和熵成分
DOI：
10.1088/1361-648x/abdff8
复制
发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Noid, W. G.
中科院分区：
文献类型：
--
作者：
Szukalo, Ryan J.;Noid, W. G.
通过消除不必要的细节，粗粒度（CG）模型为模拟高分辨率模型无法达到的尺度提供了必要的效率。然而，由于它们在原子细节上平均，控制CG自由度的有效势必然包含重要的熵贡献，这限制了它们的可转移性并使热力学性质的处理复杂化。这项工作采用双势方法来考虑CG模型的有效相互作用势的能量和熵贡献。具体来说，我们考虑了邻特苯（OTP）在玻璃化转变上方和下方的单点和三点CG模型。我们采用多尺度粗粒化（MS-CG）变分原理来确定相互作用势，准确地再现了OTP在每个状态点的全原子（AA）模型的结构特性。我们采用能量匹配变分原理来确定一个能量算符，精确地再现AA模型的分子内和分子间能量。虽然MS-CG对电位几乎是纯排斥的，但对应的对能量函数具有明显的最小值，对应于接触苯环。然后，这些能量函数确定了MS-CG相互作用势的熵分量的估计。这些熵函数准确地预测了恒定密度下大范围液态点上的MS-CG对电位。此外，熵函数还预测了能相当准确地模拟玻璃化跃迁下AA对结构的对势。因此，双势方法似乎是一种很有前途的方法来模拟AA能量学，以及预测CG有效势的温度依赖性。
By eliminating unnecessary details, coarse-grained (CG) models provide the necessary efficiency for simulating scales that are inaccessible to higher resolution models. However, because they average over atomic details, the effective potentials governing CG degrees of freedom necessarily incorporate significant entropic contributions, which limit their transferability and complicate the treatment of thermodynamic properties. This work employs a dual-potential approach to consider the energetic and entropic contributions to effective interaction potentials for CG models. Specifically, we consider one-and three-site CG models for ortho-terphenyl (OTP) both above and below its glass transition. We employ the multiscale coarse-graining (MS-CG) variational principle to determine interaction potentials that accurately reproduce the structural properties of an all-atom (AA) model for OTP at each state point. We employ an energy-matching variational principle to determine an energy operator that accurately reproduces the intra-and inter-molecular energy of the AA model. While the MS-CG pair potentials are almost purely repulsive, the corresponding pair energy functions feature a pronounced minima that corresponds to contacting benzene rings. These energetic functions then determine an estimate for the entropic component of the MS-CG interaction potentials. These entropic functions accurately predict the MS-CG pair potentials across a wide range of liquid state points at constant density. Moreover, the entropic functions also predict pair potentials that quite accurately model the AA pair structure below the glass transition. Thus, the dual-potential approach appears a promising approach for modeling AA energetics, as well as for predicting the temperature-dependence of CG effective potentials.
登录
查看更多内容
4-氰基-4-戊基联苯的系统粗粒化
影响因子：
4.2
作者：
G. Megariotis;Antonia Vyrkou;A. Leygue;D. Theodorou
通讯作者：
D. Theodorou
系统粗粒度模型的相平衡建模——状态点可转移性的比较研究。
影响因子：
3.3
作者：
Gregor Deichmann;M. Dallavalle;D. Rosenberger;N. V. D. van der Vegt
通讯作者：
N. V. D. van der Vegt
影响因子：
4.4
作者：
J. F. Rudzinski;T. Bereau
通讯作者：
T. Bereau
具有有效潜力的统计力学模型：定义、应用和热力学后果
影响因子：
4.4
作者：
F. Stillinger;H. Sakai;S. Torquato
通讯作者：
S. Torquato
DOI：
--
发表时间：
2009
期刊：
影响因子：
--
作者：
J. W. Mullinax;W. Noid
通讯作者：
W. Noid