Negrut Dan, Anitescu Mihai, El-Azab Anter, Zapol Peter
Materials Science Program, Department of Mechanical Engineering, The University of Wisconsin, Madison, WI 53706, USA.
J Nanosci Nanotechnol. 2008 Jul;8(7):3729-40.
Density functional theory can accurately predict chemical and mechanical properties of nanostructures, although at a high computational cost. A quasicontinuum-like framework is proposed to substantially increase the size of the nanostructures accessible to simulation. It takes advantage of the near periodicity of the atomic positions in some regions of nanocrystalline materials to establish an interpolation scheme for the electronic density in the system. The electronic problem embeds interpolation and coupled cross-domain optimization techniques through a process called electronic reconstruction. For the optimization of nuclei positions, computational gains result from explicit consideration of a reduced number of representative nuclei and interpolating the positions of the rest of nuclei following the quasicontinuum paradigm. Numerical tests using the Thomas-Fermi-Dirac functional demonstrate the validity of the proposed framework within the orbital-free density functional theory.
密度泛函理论可以精确预测纳米结构的化学和力学性质，尽管计算成本很高。本文提出了一种类似准连续介质的框架，以大幅增加可模拟的纳米结构尺寸。它利用纳米晶体材料某些区域中原子位置的近周期性，为系统中的电子密度建立一种插值方案。电子问题通过一个称为电子重构的过程嵌入插值和耦合跨域优化技术。对于原子核位置的优化，通过明确考虑数量减少的代表性原子核，并按照准连续介质范式对其余原子核的位置进行插值，可以获得计算收益。使用托马斯 - 费米 - 狄拉克泛函的数值测试证明了所提出框架在无轨道密度泛函理论中的有效性。
