Comparative Study of Force Fields for Molecular Dynamics Simulations of α-Glycine Crystal Growth from Solution
Comparative Study of Force Fields for Molecular Dynamics Simulations of α-Glycine Crystal Growth from Solution
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DOI：
10.1021/cg100906s
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发表时间：
2010-12-01
影响因子：
3.8
通讯作者：
Di Boon, Yi
中科院分区：
文献类型：
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作者：
Cheong, Daniel W.;Di Boon, Yi
由于晶体生长的缓慢速率和所涉及的复杂的分子间相互作用，使用分子动力学研究晶体生长是非常困难的。为了准确地执行从水溶液中晶体生长的分子动力学模拟，晶体内的相互作用以及晶体分子与水之间的相互作用都需要正确地描述。我们已经研究和比较了各种力场在α-甘氨酸结晶的分子动力学研究中的适用性。已经研究的力场包括Charmm 27，generalAMBER，OPLS-AA/L，和Gromos 53 a6由于静电相互作用预期在本体甘氨酸晶体和溶液的性质中起重要作用，还研究了从第一原理计算获得的另外五种电荷组。进行，并将α-甘氨酸晶格能、溶液密度和自扩散率的结果与可用的实验结果进行比较。还确定了溶液焓，并发现其是力场用于晶体生长研究的适用性的良好指示。一般的AMBER力场，与使用微分重叠方法的完全平衡计算得到的电荷相结合，是最佳力场导致从稍微过饱和的甘氨酸溶液在α-甘氨酸晶体的（010）面处显著的晶体生长。这种模拟提供了在分子水平上对晶体生长机制的了解。甘氨酸晶体生长涉及以正确的分子取向附着在现有晶面上的单体生长单元。通过模拟系统地研究影响晶体生长的各种因素，如温度、浓度、溶剂杂质等，以便更好地全面了解晶体生长过程
The study of crystal growth using molecular dynamics is very difficult due to the slow rate of growth and the complex intermolecular interactions involved In order to perform molecular dynamics simulations of crystal growth from aqueous solution accurately, both interactions within the crystal and interactions between the crystal molecules and water need to be described correctly In this study, we have investigated and compared various force fields for their applicability in the molecular dynamics study of alpha-glycine crystallization The force fields that have been investigated include Charmm27, general AMBER, OPLS-AA/L, and Gromos53a6 As the electrostatic interactions are expected to play a significant role in the properties of bulk glycine crystal and solution, five other charge sets obtained from first principles calculations have also been investigated Simulations in the bulk crystal and aqueous solution environments have been carried out, and results for the a-glycine lattice energy, solution densities, and self-diffusivities are compared to available experimental results The solution enthalpy has also been determined and is found to be a good indicator of the applicability of the force field for crystal growth studies The general AMBER force field, coupled with charges derived from calculations using the Complete Neglect of Differential Overlap method, is found to be the optimal force field, resulting in significant crystal growth at the (010) face of the a-glycine crystal from a slightly supersaturated glycine solution Such simulations provide insights into the mechanism of crystal growth at the molecular level We observe that a-glycine crystal growth involves monomeric growth units that attach to the existing crystal face in the correct molecular orientation This work also opens up possibilities to systematically investigate the various factors that affect crystal growth through simulations, such as temperature, concentration solvent impurities, etc so as to gain a better overall understanding of the crystal growth process