Theoretical studies for the N2-N2O van der Waals complex: The potential energy surface, intermolecular vibrations, and rotational transition frequencies.
Theoretical studies for the N2-N2O van der Waals complex: The potential energy surface, intermolecular vibrations, and rotational transition frequencies.
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DOI：
10.1063/1.4933057
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发表时间：
2011-02
期刊：
影响因子：
--
通讯作者：
R. Zheng;Limin Zheng;Yunpeng Lu;Minghui Yang
中科院分区：
文献类型：
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作者：
R. Zheng;Limin Zheng;Yunpeng Lu;Minghui Yang
对N2-N2O范德华（vdW）配合物的势能面（PES）和束缚态进行了理论研究。以8 -cc- pvtz基集补充键函数，在单、双激励耦合簇法水平上，采用三激励的非迭代摄动处理[CCSD(T)]构建了四维分子间PES。两个等效的t形全局极小值位于N2O单体的O原子靠近N2单体的位置。分子间基本振动态是通过检测波函数节点表面的方向来确定的。分子间旋散模式的计算频率为23.086 cm(-1)，与现有实验数据22.334 cm（-1）吻合较好。在基振状态下，隧道分裂可忽略不计，其值为4.2 MHz，隧道分裂随振动频率的增加而增加。计算了同位素体（14）N2-N2O和（15）N2-N2O的旋转能级和跃迁频率。理论分析结果与实验结果吻合较好，验证了该方法的准确性。
Theoretical studies of the potential energy surface (PES) and bound states are performed for the N2-N2O van der Waals (vdW) complex. A four-dimensional intermolecular PES is constructed at the level of single and double excitation coupled-cluster method with a non-iterative perturbation treatment of triple excitations [CCSD(T)] with aug-cc-pVTZ basis set supplemented with bond functions. Two equivalent T-shaped global minima are located, in which the O atom of N2O monomer is near the N2 monomer. The intermolecular fundamental vibrational states are assigned by inspecting the orientation of the nodal surface of the wavefunctions. The calculated frequency for intermolecular disrotation mode is 23.086 cm(-1), which is in good agreement with the available experimental data of 22.334 cm(-1). A negligible tunneling splitting with the value of 4.2 MHz is determined for the ground vibrational state and the tunneling splitting increases as the increment of the vibrational frequencies. Rotational levels and transition frequencies are calculated for both isotopomers (14)N2-N2O and (15)N2-N2O. The accuracy of the PES is validated by the good agreement between theoretical and experimental results for the transition frequencies and spectroscopic parameters.