Free energy of cavity formation in solvent: Computational, methodological, and physical aspects
Free energy of cavity formation in solvent: Computational, methodological, and physical aspects
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溶剂中空腔形成的自由能：计算、方法和物理方面
DOI：
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发表时间：
1995
期刊：
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通讯作者：
W. V. Gunsteren
中科院分区：
文献类型：
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作者：
T. Beutler;Daniel R. Béguelin;W. V. Gunsteren
利用分子动力学模拟技术，研究并测定了300 K和1 atm下水中空穴形成的自由能。不同的方法进行了比较：Widom粒子插入，热力学积分，微扰。结果表明，得到准确结果的最有效的方法是应用Widom粒子插入腔的热半径为0.25 nm，然后在固定的热半径与采样的热力学积分。为了在一个热半径下将结果收敛到2.5%，需要大约100 ps的模拟周期。对于略高于水分子的货车德瓦尔斯半径（0.31 nm）的热半径的收敛行为是差的，并且因此指示在腔周围的水壳中的不稳定性，并且自由能是热半径的非平滑增加函数。
With molecular dynamics simulation techniques, the free energy of cavity formation in water is investigated and determined at 300 K and 1 atm. Different methods are compared: Widom particle insertion, thermodynamic integration, and perturbation. It is shown that the most efficient way to get accurate results is to apply Widom particle insertion for cavities up to a thermal radius of 0.25 nm followed by a thermodynamic integration with sampling at fixed thermal radii. In order to converge the result to 2.5% at one thermal radius a simulation period in the order of 100 ps is needed. The convergence behavior for thermal radii slightly above the van der Waals radius of a water molecule (0.31 nm) is poor and thus indicates instabilities in the water shell surrounding the cavity and that the free energy is a nonsmoothly increasing function of the thermal radius.