Kim Soo Young, Hammes-Schiffer Sharon
Department of Chemistry, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
J Chem Phys. 2006 Jun 28;124(24):244102. doi: 10.1063/1.2206175.
A hybrid quantum/classical molecular dynamics approach is applied to a proton transfer reaction represented by a symmetric double well system coupled to a dissipative bath. In this approach, the proton is treated quantum mechanically and all bath modes are treated classically. The transition state theory rate constant is obtained from the potential of mean force, which is generated along a collective reaction coordinate with umbrella sampling techniques. The transmission coefficient, which accounts for dynamical recrossings of the dividing surface, is calculated with a reactive flux approach combined with the molecular dynamics with quantum transitions surface hopping method. The hybrid quantum/classical results agree well with numerically exact results in the spatial-diffusion-controlled regime, which is most relevant for proton transfer in proteins. This hybrid quantum/classical approach has already been shown to be computationally practical for studying proton transfer in large biological systems. These results have important implications for future applications to hydrogen transfer reactions in solution and proteins.
一种混合量子/经典分子动力学方法被应用于一个由与耗散浴耦合的对称双阱系统所代表的质子转移反应。在这种方法中，质子用量子力学方法处理，所有浴模式用经典方法处理。过渡态理论速率常数从平均力势获得，平均力势是通过伞形采样技术沿着集体反应坐标生成的。考虑到分隔面的动态再穿越的透射系数，是用反应通量方法结合量子跃迁表面跳跃分子动力学方法计算的。混合量子/经典结果与空间扩散控制区域的数值精确结果吻合良好，该区域与蛋白质中的质子转移最为相关。这种混合量子/经典方法已被证明在研究大型生物系统中的质子转移方面在计算上是可行的。这些结果对未来在溶液和蛋白质中的氢转移反应的应用具有重要意义。
