Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431, USA.
J Chem Phys. 2013 Jul 28;139(4):044309. doi: 10.1063/1.4811653.
We present a global ground-state potential energy surface for N4 suitable for treating high-energy vibrational-rotational energy transfer and collision-induced dissociation in N2-N2 collisions. To obtain the surface, complete active space second-order perturbation theory calculations were performed for the ground singlet state with an active space of 12 electrons in 12 orbitals and the maug-cc-pVTZ triple zeta basis set. About 17,000 ab initio data points have been calculated for the N4 system, distributed along nine series of N2 + N2 geometries and three series of N3 + N geometries. The six-dimensional ground-state potential energy surface is fitted using least-squares fits to the many-body component of the electronic energies based on permutationally invariant polynomials in bond order variables.
我们提出了一个适用于 N2-N2 碰撞中高能振动-转动能量转移和碰撞诱导离解的 N4 全局基态势能面。为了获得该表面，我们对 12 个轨道中 12 个电子的活性空间进行了完全活性空间二阶微扰理论计算，并采用 maug-cc-pVTZ 三重 zeta 基组。我们已经针对 N4 体系计算了大约 17000 个从头算数据点，这些数据点沿九条 N2+N2 几何构型系列和三条 N3+N 几何构型系列分布。基于键序变量的置换不变多项式，使用对电子能量的多体分量进行最小二乘拟合，对六维基态势能面进行拟合。
