【作者】 马永涛； 李辉；

【Author】 Yong-Tao Ma;Hui Li;Institute of Theoretical Chemistry,Jilin University;Institute of Theoretical Chemistry, Jilin University;

【机构】 吉林大学理论化学研究所；

【摘要】 本工作报道了CH₃F-Rg（Rg=He、Ne、Ar）体系包含CH₃F分子红外活性强的C-F伸缩的振动四维高精度势能面。这些体系振动平均后的势能面通过非线性拟合成摩斯长程势（MLR）形式。[1]拟合的标准差均小于0.1个波数。这三个体系的势能面都存在一个T-型结构的最小值点和两个局部最小值点以及两个过渡态。势能面的能量值、阱深和能垒大小均按CH₃F-He、CH₃F-Ne和CH₃F-Ar排列。随后,这些势能面被运用于体系的能级计算中。我们用分子对称群理论去构造体系的包含对称性的波函数,用联合离散变量表象和有限基组表象的方法生成其矩阵元,用Lanczos迭代方法求解体系的薛定谔方程。[2]基于波函数分析,我们指认了体系的能级并根据选择定则预测了体系的红外、微波光谱。这些光谱的跃迁强度也通过理论计算给出。更多还原

【Abstract】 In this work, we reported the four-dimensional ab initio intermolecular potential energy surfaces for CH₃F-Rg（Rg=He,Ne,Ar） systems that explicitly incorporates dependence on the C-F stretching normal node of the CH₃F molecule. Analytical three-dimensional PESs for these systems are obtained by least-squares fitting the vibrationally averaged potentials to the Morse/Long-Range potential function form. One T-shaped global minimum and two global minimums are found in these PESs. The energy, well depth and the barriers are arranged by CH₃F-He, CH₃F-Ne and CH₃F-Ar. With the 3D PESs, we employ Lanczos algorithm to calculate ro-vibrational levels of the dimer system. In detail, we use molecule symmetry group theory to get parity-adapted basis, use combined DVR and FBR method to produce the matrix elements. Base on the wavefunction analysis, we assign the energy levels. Use the knowledge of selection rule, we predict the microwave and infrared spectra of these systems. The transition intensities of these spectra are also given.更多还原