Highly accurate computation of free energies in complex systems through horsetail QM/MM molecular dynamics combined with free-energy perturbation theory
Highly accurate computation of free energies in complex systems through horsetail QM/MM molecular dynamics combined with free-energy perturbation theory
复制标题
通过马尾 QM/MM 分子动力学结合自由能微扰理论高精度计算复杂系统中的自由能
DOI：
--
复制
发表时间：
2017
影响因子：
1.7
通讯作者：
M. Ruiz‐López
中科院分区：
文献类型：
--
作者：
M. Martins‐Costa;M. Ruiz‐López
我们报告了一种方法来计算非常准确的自由能值在复杂的系统中使用混合QM/MM方法。该方法结合了分子动力学中的马尾抽样技术和自由能微扰理论中的双能级技术。前者是一种特殊类型的多分子动力学，专门为QM/MM模拟的高效并行化而设计。后者允许从在较低的QM/MM水平下获得的参考采样估计在高QM/MM水平下的自由能校正。该方法是通过研究过氧化氢在蒸汽-液体水界面，一个系统的相当大的大气和环境的相关性。本文在CCSD（T）/aug-cc-pVTZ理论水平上计算了溶质扭转运动的自由能分布。平衡角为87.7°，顺式和反式过渡态的自由能垒分别为4.3和1.4kcal/mol。这些值与气相势能面在等效计算水平（分别为112.8°、7.3和1.1 kcal/mol）上有显著差异，表明过氧化氢在水滴上的吸附可能对其大气化学产生重大影响。
We report a method to calculate very accurate free-energy values in complex systems using hybrid QM/MM approaches. The method combines the recently developed horsetail sampling technique in molecular dynamics and the dual-level technique derived from free-energy perturbation theory. The former is a particular type of multiple molecular dynamics that has been specifically designed for an efficient parallelization of QM/MM simulations. The latter allows estimating free-energy corrections at a high QM/MM level from a reference sampling obtained at a lower QM/MM level. The methodology is illustrated through the study of hydrogen peroxide at the vapor–liquid water interface, a system of considerable atmospheric and environmental relevance. We focus on the calculation of the free-energy profile for the torsional motion of the solute at the CCSD(T)/aug-cc-pVTZ level of theory. It is shown that the equilibrium angle is 87.7°, and that the free-energy barriers for cisoid and transoid transition states are 4.3 and 1.4 kcal/mol, respectively. These values are significantly different from the gas phase potential energy surface at the equivalent computational level (112.8°, 7.3 and 1.1 kcal/mol, respectively) suggesting that adsorption of hydrogen peroxide on water droplets could have major implications on its atmospheric chemistry.
影响因子：
5.5
作者：
Rackers JA;Wang Z;Lu C;Laury ML;Lagardère L;Schnieders MJ;Piquemal JP;Ren P;Ponder JW
通讯作者：
Ponder JW