变分代数能量自洽法研究Li_2分子部分电子态的解析势能

在课题组前期建立的计算双核分子体系解析势能函数的代数能量自洽法(algebraic energy consistent method,AECM)的基础上,引入了经改进得到的精确研究双核分子完全振动能谱的变分代数法(variational algebraic method,VAM),获得了计算双核分子体系精确解析势能函数的变分代数能量自洽法(variational algebraic energy consistent method,VAECM)。基于有限的精确实验振动能谱数据,利用VAECM方法研究了Li_2分子1~3Δ_g,3~3Σ_g~+,1~3Σ_g~-和b~3Π_u等4个电子态的完全振动能谱和解析势能函数。获得了各电子态包含高阶的振动光谱常数、完全振动能谱、振动力常数fn和势能展开系数an,并通过可调变分参数λ最终确定了VAECM解析势能函数的具体表达形式。计算结果与其他方法的研究结果进行了比较,VAECM方法获得的振动能谱数据和势能解析表达形式能更好地描述这些电子态在渐近区和离解区的物理行为,消除了利用前期AECM方法研究这些电子态在离解区出现的非物理势垒现象。

Studies on the Analytical Potential Energies for Partial Electronic States of Li2 with Variational Algebraic Energy Consistent Method

The full vibrational spectra especially those high-lying vibrational energies in the dissociation region of four specific electronic states 13Δg,33Σ+g ,13Σ-g and b3Πu have been obtained by using the improved variational algebraic method (VAM). The analytical potential energy functions (APEFs)of these electronic states are also determined with corresponding adj ustable parameterλby using the variational algebraic energy consistent method (VAECM)based on the VAM vibrational spectra.The full vibrational energies,vibrational spectroscopic constants,force constants fn,and expansion coefficients an of the VAECM potential are also tabulated for each electronic state in this study.The results show that the VAECM analytical potentials are superi-or to some other widely used analytical ones,and do not have the unphysical tiny barriers existing in the precious AECM potentials.