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本文采用含Davidson校正的多参考组态相互作用MRCI+Q方法以及aug-cc-pVQZ基组计算了N2H体系的基态与第一激发态近24000个从头算能量点,使用三次样条插值法构建了高精度的全域绝热势能面.基态势能面具有一个极小点以及高于极小点0.44 eV的鞍点.基于该势能面上发生的N(~4S)+NH(X~3∑~-)→H(~2S)+N_2(X~1∑_g~g)反应是一个无能垒的放热反应,放热量为6.172 eV,比过去的势能面更接近实验值(5.956 eV).基态与第一激发态势能面间存在明显的锥形交叉,说明两个态之间存在非绝热耦合.此外,采用Lanczos算法预测了基态N_2H分子的振动能级.
In this paper, we calculate the ground state and the first excited state of nearly 24,000 ab initio energy points in the N2H system using the MRCI + Q method and the aug-cc-pVQZ basis set with the multi-reference configuration interaction with Davidson correction. The cubic spline interpolation method is used to construct A highly accurate global adiabatic potential energy surface is proposed.The ground state potential energy surface has a minimum point and a saddle point above the minimum point of 0.44 eV.Based on the N (~ 4S) + NH (X ~ 3Σ ~ -) → H (~ 2S) + N_2 (X ~ 1Σ_g ~ g) is a non-barrier exothermic reaction with an exothermic heat of 6.172 eV which is closer to the experimental value (5.956 eV) than the previous potential energy surface. An obvious conical intersection exists between the excited states and the non-adiabatic coupling between the two states.In addition, Lanczos algorithm is used to predict the vibrational level of ground state N 2 H molecules.