arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2106.05415cond-mat.stat-mechcond-mat.mtrl-sci
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自由能景观,扩散系数和动力学速率从过渡路径

Free Energy Landscapes, Diffusion Coefficients, and Kinetic Rates from Transition Paths

Karen Palacio-Rodriguez, Fabio Pietrucci

摘要:

我们解决的问题,构建精确的数学模型的动态的复杂系统投影到一个集体变量。为了这个目的,我们引入一个概念上简单而有效的算法估计参数的朗之万和福克-普朗克方程从一组短,可能出平衡分子动力学轨迹,例如从过渡路径采样或作为放松从高自由能配置。该方法基于短时传播子的任意显式表达式,使模型似然最大化,因此可以应用于不同的演化方程。我们证明了模型系统上的算法的数值效率和鲁棒性,我们应用它来重建C60和C240富勒烯分子在显式水中的投影动态。我们的方法允许重建准确的热力学和动力学的活化过程,即自由能景观,扩散系数和动力学速率。与现有的增强采样方法相比,我们直接利用短无偏轨迹在一个有竞争力的计算成本。

英文摘要:

We address the problem of constructing accurate mathematical models of the dynamics of complex systems projected on a collective variable. To this aim we introduce a conceptually simple yet effective algorithm for estimating the parameters of Langevin and Fokker-Planck equations from a set of short, possibly out-of-equilibrium molecular dynamics trajectories, obtained for instance from transition path sampling or as relaxation from high free-energy configurations. The approach maximizes the model likelihood based on any explicit expression of the short-time propagator, hence it can be applied to different evolution equations. We demonstrate the numerical efficiency and robustness of the algorithm on model systems, and we apply it to reconstruct the projected dynamics of pairs of C60 and C240 fullerene molecules in explicit water. Our methodology allows reconstructing the accurate thermodynamics and kinetics of activated processes, namely free energy landscapes, diffusion coefficients, and kinetic rates. Compared to existing enhanced sampling methods, we directly exploit short unbiased trajectories at a competitive computational cost.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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