Building the bridge from atomistic to stochastic modelling of nanoscale friction phenomena

搭建纳米级摩擦现象从原子建模到随机建模的桥梁

• 批准号: RGPIN-2015-04486
• 负责人: Evstigneev, Mykhaylo
• 金额: $ 1.6万
• 依托单位: Memorial University of Newfoundland
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=589832
• 关键词: Building; bridge; atomistic; stochastic; modelling

Direct molecular dynamic simulation of a nanoscale object involves numerical integration of the equations of motion for all its atoms. This approach is exact, but it has severe size and time-scale limitations. Stochastic modelling overcomes these limitations by focusing on only a small subset of the relevant degrees of freedom, termed "the system". The remaining large number of the irrelevant ones, denoted as "the heat bath", are not simulated explicitly, but taken into account by (i) renormalizing the forces acting on and between the system coordinates, (ii) including dissipative forces describing the energy transfer from the system into the heat bath, and (iii) introducing random forces describing the effect of thermal motion of the heat-bath atoms on the system.

纳米级物体的直接分子动力学模拟涉及其所有原子的运动方程的数值积分。这种方法是准确的，但它有严重的规模和时间尺度的限制。随机建模克服了这些限制，只关注一个小的子集的相关自由度，称为“系统”。其余大量的不相关的，表示为“热浴”，没有明确模拟，但考虑到（i）重新正规化的力作用在系统坐标和之间，（ii）包括耗散力描述的能量转移从系统到热浴，和（iii）引入随机力描述热浴原子的热运动对系统的影响。