Nangia Shikha, Truhlar Donald G
Department of Chemistry and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431, USA.
J Chem Phys. 2006 Mar 28;124(12):124309. doi: 10.1063/1.2168447.
We used multiconfiguration quasidegenerate perturbation theory and the fourfold-way direct diabatization scheme to calculate ab initio potential-energy surfaces at 3600 nuclear geometries of NH3. The calculations yield the adiabatic and diabatic potential-energy surfaces for the ground and first electronically excited singlet states and also the diabatic coupling surfaces. The diabatic surfaces and coupling were fitted analytically to functional forms to obtain a permutationally invariant 2 x 2 diabatic potential-energy matrix. An analytic representation of the adiabatic potential-energy surfaces is then obtained by diagonalizing the diabatic potential-energy matrix. The analytic representation of the surfaces gives an analytic representation of the four-dimensional conical intersection seam which is discussed in detail.
我们使用多组态准简并微扰理论和四重直接 diabatic 方案，在 3600 个 NH₃ 核几何构型下从头计算势能面。计算得出了基态和第一电子激发单重态的绝热和 diabatic 势能面，以及 diabatic 耦合面。将 diabatic 面和耦合进行解析拟合以得到函数形式，从而获得一个具有置换不变性的 2×2 diabatic 势能矩阵。然后通过对 diabatic 势能矩阵进行对角化，得到绝热势能面的解析表示。这些面的解析表示给出了四维锥形交叉缝的解析表示，并对此进行了详细讨论。
