(NH)的全维从头算势能面和偶极矩面

A full-dimensional ab initio potential energy and dipole moment surfaces for (NH).

作者信息

Yang Shuo, Zhang Zhaojun, Zhang Dong H

机构信息

State Key Laboratory of Molecular Reaction Dynamics and Center for Theoretical and Computational Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, People's Republic of China.

出版信息

J Chem Phys. 2021 Oct 28;155(16):164306. doi: 10.1063/5.0072063.

DOI:10.1063/5.0072063

PMID:34717358

Abstract

A full-dimensional ab initio potential energy surface (PES) and dipole moment surface (DMS) for the ammonia dimer (NH) are reported. The database of the PES consists of 27 736 ab initio energy points and all of these points were calculated at the UCCSD(T)-F12a/AVTZ level. The PES was fitted by using the fundamental invariant neural network (FI-NN) method that satisfies the permutational symmetry of identical atoms, and the root mean square fitting error for the PES is very small as low as 0.562 meV. The geometries for the (NH) DMS are the same as those used for the PES and are calculated at the XYG3/AVTZ level. This PES can describe a variety of internal floppy motions, including all kinds of vibrational modes no matter intermolecular or intramolecular. The CCSD(T)-PES can dissociate correctly to two NH monomers, with D = 1135.55 cm (13.58 kJ/mol) which agrees accurately with the 13.5 ± 0.3 kJ/mol predicted by previous work.

摘要

报道了氨二聚体（NH₃）₂的全维从头算势能面（PES）和偶极矩面（DMS）。PES数据库由27736个从头算能量点组成，所有这些点均在UCCSD(T)-F12a/AVTZ水平上计算得出。通过使用满足相同原子置换对称性的基本不变神经网络（FI-NN）方法对PES进行拟合，PES的均方根拟合误差非常小，低至0.562毫电子伏特。（NH₃）₂ DMS的几何结构与PES所用的相同，且在XYG3/AVTZ水平上计算得出。该PES能够描述各种内部松弛运动，包括各种振动模式，无论是分子间还是分子内的。CCSD(T)-PES能够正确解离为两个NH₃单体，解离能D = 1135.55厘米⁻¹（13.58千焦/摩尔），这与先前工作预测的13.5±0.3千焦/摩尔精确吻合。