采用从头计算的多参考组态CI方法(MRCI)和B原子Dunning s相关调和基函数含扩散基的大基组aug cc pVQZ对B+2分子的基态和低激发态的势能曲线进行计算。利用Huxley函数、Murrell Sorbie函数和最小二乘法拟合出了解析势能函数,并以此为基...采用从头计算的多参考组态CI方法(MRCI)和B原子Dunning s相关调和基函数含扩散基的大基组aug cc pVQZ对B+2分子的基态和低激发态的势能曲线进行计算。利用Huxley函数、Murrell Sorbie函数和最小二乘法拟合出了解析势能函数,并以此为基础计算出光谱常数。通过比较发现:Huxley函数比MS函数的拟合方差更小,能更好地再现分子中原子间相互作用。采用两种函数所得解析势能函数与从头计算势能曲线间的误差RMS均远小于化学精度4.184kJ/mol的要求,表明所得解析势能函数很好地再现了这些态中原子间的相互作用情况,可用于更广泛的研究。展开更多
The potential energy curves（PECs） of the first electronic excited state of S2（a^1△g） are calculated employing a multi-reference configuration interaction method with the Davidson correction in combination with a ...The potential energy curves（PECs） of the first electronic excited state of S2（a^1△g） are calculated employing a multi-reference configuration interaction method with the Davidson correction in combination with a series of correlationconsistent basis sets from Dunning： aug-cc-p VX Z（X = T, Q, 5, 6）. In order to obtain PECs with high accuracy, PECs calculated with aug-cc-p V（Q, 5）Z basis sets are extrapolated to the complete basis set limit. The resulting PECs are then fitted to the analytical potential energy function（APEF） using the extended Hartree–Fock approximate correlation energy method. By utilizing the fitted APEF, accurate and reliable spectroscopic parameters are obtained, which are consistent with both experimental and theoretical results. By solving the Schr o¨dinger equation numerically with the APEFs obtained at the AV6 Z and the extrapolated AV（Q, 5）Z level of theory, we calculate the complete set of vibrational levels, classical turning points, inertial rotation and centrifugal distortion constants.展开更多
A new method on constructing analytical potential energy functions is presented, and then a relatively universal analytical potential energy function for precisely calculating the spectra of ＇iatomic molecules and io...A new method on constructing analytical potential energy functions is presented, and then a relatively universal analytical potential energy function for precisely calculating the spectra of ＇iatomic molecules and ions is derived. Furthermore, six kinds of common potential energy curves containing three main potential curves i,e. steady state, metastable state and repulsive state are obtained from this potential energy function. Finally, spectroscopic parameters of thirteen diatomic molecules and ions including BeD-X^2∑＋, BeT-X^2∑^＋ and Na2-X^1∑g^＋ etc are calculated by using the potential function, as a consequence, all calculation results are in good agreement with experimental data.展开更多
文摘采用从头计算的多参考组态CI方法(MRCI)和B原子Dunning s相关调和基函数含扩散基的大基组aug cc pVQZ对B+2分子的基态和低激发态的势能曲线进行计算。利用Huxley函数、Murrell Sorbie函数和最小二乘法拟合出了解析势能函数,并以此为基础计算出光谱常数。通过比较发现:Huxley函数比MS函数的拟合方差更小,能更好地再现分子中原子间相互作用。采用两种函数所得解析势能函数与从头计算势能曲线间的误差RMS均远小于化学精度4.184kJ/mol的要求,表明所得解析势能函数很好地再现了这些态中原子间的相互作用情况,可用于更广泛的研究。
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11304185 and 11074151)
文摘The potential energy curves（PECs） of the first electronic excited state of S2（a^1△g） are calculated employing a multi-reference configuration interaction method with the Davidson correction in combination with a series of correlationconsistent basis sets from Dunning： aug-cc-p VX Z（X = T, Q, 5, 6）. In order to obtain PECs with high accuracy, PECs calculated with aug-cc-p V（Q, 5）Z basis sets are extrapolated to the complete basis set limit. The resulting PECs are then fitted to the analytical potential energy function（APEF） using the extended Hartree–Fock approximate correlation energy method. By utilizing the fitted APEF, accurate and reliable spectroscopic parameters are obtained, which are consistent with both experimental and theoretical results. By solving the Schr o¨dinger equation numerically with the APEFs obtained at the AV6 Z and the extrapolated AV（Q, 5）Z level of theory, we calculate the complete set of vibrational levels, classical turning points, inertial rotation and centrifugal distortion constants.
基金the National Natural Science Foundation of China (40274044)
文摘A new method on constructing analytical potential energy functions is presented, and then a relatively universal analytical potential energy function for precisely calculating the spectra of ＇iatomic molecules and ions is derived. Furthermore, six kinds of common potential energy curves containing three main potential curves i,e. steady state, metastable state and repulsive state are obtained from this potential energy function. Finally, spectroscopic parameters of thirteen diatomic molecules and ions including BeD-X^2∑＋, BeT-X^2∑^＋ and Na2-X^1∑g^＋ etc are calculated by using the potential function, as a consequence, all calculation results are in good agreement with experimental data.
