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)
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
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.
Received: 21 February 2006
Revised: 09 December 2006
Accepted manuscript online:
PACS:
31.15.-p
(Calculations and mathematical techniques in atomic and molecular physics)
Fund: 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
Cite this article:
Yu Ben-Hai(余本海), Shi De-Heng(施德恒), Sun Jin-Feng(孙金锋), Zhu Zun-Lue(朱遵略), Liu Yu-Fang(刘玉芳), and Yang Xiang-Dong(杨向东) Ab initio calculation on accurate analytic potential energy functions and harmonic frequencies of c3$\Sigma$+g and B1$\Pi$u states of dimer 7Li2 2007 Chinese Physics 16 2371
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