中国物理B ›› 2007, Vol. 16 ›› Issue (8): 2371-2377.doi: 10.1088/1009-1963/16/8/036

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Ab initio calculation on accurate analytic potential energy functions and harmonic frequencies of c3∑+g and B1∏u states of dimer 7Li2

余本海1, 施德恒1, 孙金锋2, 刘玉芳2, 朱遵略3, 杨向东4   

  1. (1)College of Physics & Electronic Engineering, Xinyang Normal University, Xinyang 464000, China;College of Physics & Information Engineering, Henan Normal University, Xinxiang 453007, China; (2)College of Physics & Information Engineering, Henan Normal University, Xinxiang 453007, China; (3)College of Physics & Information Engineering, Henan Normal University, Xinxiang 453007, China ;Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China; (4)Institute of Atomi
  • 收稿日期:2006-02-21 修回日期:2006-12-09 出版日期:2007-08-20 发布日期:2007-08-20
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No~10574039), the Henan Innovation for University Prominent Research Talents (Grant No~2006KYCX002) and the National Natural Science Foundation of Education Bureau of Henan Prov

Ab initio calculation on accurate analytic potential energy functions and harmonic frequencies of c3$\Sigma$+g and B1$\Pi$u states of dimer 7Li2

Yu Ben-Hai(余本海)a) b), Shi De-Heng(施德恒) a) b)†, Sun Jin-Feng(孙金锋)b), Zhu Zun-Lue(朱遵略)b) c), Liu Yu-Fang(刘玉芳)b), and Yang Xiang-Dong(杨向东)c)   

  1. a College of Physics & Electronic Engineering, Xinyang Normal University, Xinyang 464000, Chinab College of Physics & Information Engineering, Henan Normal University, Xinxiang 453007, China; c Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China
  • Received:2006-02-21 Revised:2006-12-09 Online:2007-08-20 Published:2007-08-20
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No~10574039), the Henan Innovation for University Prominent Research Talents (Grant No~2006KYCX002) and the National Natural Science Foundation of Education Bureau of Henan Prov

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摘要： The comparison between single-point energy scanning (SPES) and geometry optimization (OPT) in determining the equilibrium geometries of c3\Sigma+g and B1Ⅱ u states of dimer 7Li2 is made at numerous basis sets by using a symmetry-adapted-cluster configuration-interaction (SAC-CI) method in the Gaussian 03 program package. In this paper the difference of the equilibrium geometries obtained by SPES and by OPT is reported. The results obtained by SPES are found to be more reasonable than those obtained by OPT in full active space at the present SAC-CI level of theory. And the conclusion is attained that the cc-PVTZ is a most suitable basis set for these states. The calculated dissociation energies and equilibrium geometries are 0.8818 eV and 0.3090 nm for c3\Sigma+g state, and 0.3668 eV and 0.2932 nm for B1Ⅱ u state respectively. The potential energy curves are calculated over a wide internuclear distance range from about 2.5a0 to 37a0 and have a least-squares fit into the Murrell--Sorbie function. According to the calculated analytic potential energy functions, the harmonic frequencies (\omegae and other spectroscopic data (\omegae \chie , \Be and \alphae are calculated. Comparison of the theoretical determinations at present work with the experiments and other theories clearly shows that the present work is the most complete effort and thus represents an improvement over previous theoretical results.

关键词: molecular structure and potential energy function, atomic and molecular collision, dimer, excited state

Abstract: The comparison between single-point energy scanning (SPES) and geometry optimization (OPT) in determining the equilibrium geometries of c3$\Sigma$+g and B1$\Pi$u states of dimer 7Li2 is made at numerous basis sets by using a symmetry-adapted-cluster configuration-interaction (SAC-CI) method in the Gaussian 03 program package. In this paper the difference of the equilibrium geometries obtained by SPES and by OPT is reported. The results obtained by SPES are found to be more reasonable than those obtained by OPT in full active space at the present SAC-CI level of theory. And the conclusion is attained that the cc-PVTZ is a most suitable basis set for these states. The calculated dissociation energies and equilibrium geometries are 0.8818 eV and 0.3090 nm for c3$\Sigma$+g state, and 0.3668 eV and 0.2932 nm for B1$\Pi$ u state respectively. The potential energy curves are calculated over a wide internuclear distance range from about 2.5a0 to 37a0 and have a least-squares fit into the Murrell--Sorbie function. According to the calculated analytic potential energy functions, the harmonic frequencies (\omegae and other spectroscopic data ($\omega$e$\chi$e , Be and $\alpha$e are calculated. Comparison of the theoretical determinations at present work with the experiments and other theories clearly shows that the present work is the most complete effort and thus represents an improvement over previous theoretical results.

Key words: molecular structure and potential energy function, atomic and molecular collision, dimer, excited state

中图分类号:  (Calculations and mathematical techniques in atomic and molecular physics)

  • 31.15.-p
31.15.V- (Electron correlation calculations for atoms, ions and molecules) 31.50.-x (Potential energy surfaces) 33.15.Fm (Bond strengths, dissociation energies)