Applying Density-Functional Theory to Large Molecules: Theoretical and Computational Development

在化学系理论和计算化学项目的资助下，杨教授将开发基于密度泛函理论的计算大分子电子结构的理论和计算方法。他将沿着以下两个方向推广最近的进展：(1)不使用分子轨道直接计算电子密度将由新开发的“分而治之”算法进行。这种方法将分子分成多个子系统，并将总电子密度和总能量确定为所有子系统贡献的总和。此外，它还非常适合并行计算。将努力在大规模并行计算机上实施这一理论，每个处理器处理一个子系统。(2)用局部投影法求解Kohn-Sham密度泛函方程是一种更有效的方法。本项目将开发的新算法将增强密度泛函理论的预测能力，并将使对复杂的化学和生物现象的可能的理论研究，否则用传统方法是不可能的。

With this grant in the Theoretical and Computational Chemistry Program of the Chemistry Division, Professor Yang will develop theoretical and computational methods for computing the electronic structure of large molecules based on density functional theory. He will extend recent progress along the following two directions: (1) The direct calculation of electron density without using molecular orbitals will be undertaken by a newly developed "divide and conquer" algorithm. This method divides the molecule into subsystems and determines the total electron density and energy as the sum of all subsystem contributions. It is, in addition, well-suited for parallel computation. Effort will be made to implement the theory on massively parallel computers, with each processor handling one subsystem. (2) A more efficient way of implementing the solution of the Kohn-Sham density functional equations will be developed by making use of a local projection method. %%% The new algorithms which will be developed in this project will enhance the predictive power of density functional theory and will make possible theoretical studies of complex chemical and biological phenomena that are otherwise impossible by conventional methods.