Full-dimensional diabatic potential energy surfaces including dissociation: the ²E″ state of NO₃.
Full-dimensional diabatic potential energy surfaces including dissociation: the ²E″ state of NO₃.
复制标题
DOI：
10.1063/1.4879655
复制
发表时间：
2014-06
期刊：
影响因子：
--
通讯作者：
W. Eisfeld;O. Vieuxmaire;A. Viel
中科院分区：
文献类型：
--
作者：
W. Eisfeld;O. Vieuxmaire;A. Viel
提出了一种适用于动力学计算的精确的全维耦合非绝热势能面的生成方案。该方案成功地模拟了NO3自由基的(2)E“态的两层表面。给出了NO-₃⁻阴离子基态的精确势能面。这两个表面都是基于高级从头计算。该模型由一个非绝热势阵组成，根据对称坐标的对称多项式将其展开到高阶。坐标的选择是获得势能面精度的关键，并对此进行了详细的讨论。第二个核心方面是生成参考数据以适应模型的扩展系数，为此提出了一种随机方法。第三个要素是一种新的、简单的方案来处理势能面的问题区域，这是由于高维问题不可避免地通过参考数据进行大量欠采样而产生的。最终的解析非绝热表面被用来计算NO-₃⁻的最低振动能级和NO-₃⁻在(2)E“态导致中性自由基的光电子脱离谱。模拟结果与已有实验数据的一致性表明了所提方案的有效性和所获得的势能面的高质量。
A scheme to produce accurate full-dimensional coupled diabatic potential energy surfaces including dissociative regions and suitable for dynamical calculations is proposed. The scheme is successfully applied to model the two-sheeted surface of the (2)E″ state of the NO3 radical. An accurate potential energy surface for the NO₃⁻ anion ground state is developed as well. Both surfaces are based on high-level ab initio calculations. The model consists of a diabatic potential matrix, which is expanded to higher order in terms of symmetry polynomials of symmetry coordinates. The choice of coordinates is key for the accuracy of the obtained potential energy surfaces and is discussed in detail. A second central aspect is the generation of reference data to fit the expansion coefficients of the model for which a stochastic approach is proposed. A third ingredient is a new and simple scheme to handle problematic regions of the potential energy surfaces, resulting from the massive undersampling by the reference data unavoidable for high-dimensional problems. The final analytical diabatic surfaces are used to compute the lowest vibrational levels of NO₃⁻ and the photo-electron detachment spectrum of NO₃⁻ leading to the neutral radical in the (2)E″ state by full dimensional multi-surface wave-packet propagation for NO3 performed using the Multi-Configuration Time Dependent Hartree method. The achieved agreement of the simulations with available experimental data demonstrates the power of the proposed scheme and the high quality of the obtained potential energy surfaces.