Quantum chemistry based force field for simulations of poly(propylene oxide) and its oligomers
Quantum chemistry based force field for simulations of poly(propylene oxide) and its oligomers
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基于量子化学的力场模拟聚环氧丙烷及其低聚物
DOI：
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发表时间：
1998
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通讯作者：
D. Bedrov
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文献类型：
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作者：
Grant D. Smith;O. Borodin;D. Bedrov
我们提出了用于模拟聚环氧丙烷（PPO）及其低分子量低聚物的原子力场。力场经过参数化，可准确再现 1,2-二甲氧基丙烷 (DMP) 和 3,6-二甲基二甘醇二甲醚 (DMD) 中的相对构象能量和旋转能垒，如通过高级从头算电子结构计算确定的。部分原子电荷已被确定，可以准确再现由量子化学确定的 DMP 和 DMD 重要构象异构体的静电势和偶极矩，同时产生用于 PPO 模拟的电荷中性重复单元。通过比较 DMP 的气相分子动力学模拟与气相 NMR 邻位耦合测量，检查力场准确再现构象能的能力。发现模拟中的 O-C*-C-O 键的总体与实验确定的值非常一致。通过比较来自分子动力学模拟的液体 DMP 的 PVT 数据与实验，并使用基于量子化学的力场进行醚-水相互作用的预测和高级从头计算来检查非键相互作用的准确性。在这两种情况下都发现了良好的一致性。
We present an atomistic force field for simulations of poly(propylene oxide) (PPO) and its low molecular weight oligomers. The force field is parametrized to accurately reproduce the relative conformer energies and rotational energy barriers in 1,2-dimethoxypropane (DMP) and 3,6-dimethyl diglyme (DMD) as determined from high-level ab initio electronic structure calculations. Partial atomic charges have been determined to accurately reproduce the electrostatic potential and dipole moments of important conformers of DMP and DMD as determined from quantum chemistry while yielding a charge neutral repeat unit for use in PPO simulations. The ability of the force field to accurately reproduce conformational energies is examined by comparing gas-phase molecular dynamics simulations of DMP with gas-phase NMR vicinal coupling measurements. The populations for the O-C*-C-O bond from simulations are found to be in good agreement with values determined from the experiments. The accuracy of the nonbonded interactions is examined through comparison of PVT data for liquid DMP from molecular dynamics simulations with experiment and predictions of DMP-water interactions using a quantum chemistry based force field for ether-water interactions with high-level ab initio calculations. In both cases good agreement is found.