Department of Chemistry, University of Perugia, via Elce di Sotto, 8, Perugia, 06123, Italy.
J Comput Chem. 2013 Dec 5;34(31):2668-76. doi: 10.1002/jcc.23415. Epub 2013 Aug 26.
A new six-dimensional (6D) global potential energy surface (PES) is proposed for the full range description of the interaction of the N2(1Σg+)+N2(1Σg+) system governing collisional processes, including N atom exchange. The related potential energy values were determined using high-level ab initio methods. The calculations were performed at a coupled-cluster with single and double and perturbative triple excitations level of theory in order to have a first full range picture of the PES. Subsequently, in order to accurately describe the stretching of the bonds of the two interacting N2 molecules by releasing the constraints of being considered as rigid rotors, for the same molecular geometries higher level of theory multi reference calculations were performed. Out of the calculated values a 6D 4-atoms global PES was produced for use in dynamical calculations. The ab initio calculations were made possible by the combined use of High Throughput Computing and High Performance Computing techniques within the frame of a computing grid empowered molecular simulator.
提出了一个新的六维（6D）全局势能面（PES），用于描述 N2(1Σg+)+N2(1Σg+)体系相互作用的全范围，该体系控制着包括 N 原子交换在内的碰撞过程。相关的势能值是使用高精度的从头算方法确定的。计算是在耦合簇加上单重和双重以及微扰三重激发理论水平上进行的，以便对 PES 有一个完整的初步描述。随后，为了准确描述两个相互作用的 N2 分子的键的拉伸，释放被认为是刚性转子的约束，对相同的分子几何形状，进行了更高水平的理论多参考计算。从计算值中，生成了一个用于动力学计算的 6D 4 原子全局 PES。通过在计算网格赋能的分子模拟器的框架内，结合使用高通量计算和高性能计算技术，实现了从头算计算。
