Acta Phys. -Chim. Sin. ›› 2006, Vol. 22 ›› Issue (07): 780-785.doi: 10.3866/PKU.WHXB20060703

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Study on the Characteristics of the Ground States and Excited States of He2+ and He2++ Molecule Ions

ZHANG Yun-Guang;GAO Tao;LI Gui-Xia;ZHANG Chuan-Yu;CHEN Dong;ZHU Zheng-He   

  1. Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, P. R. China
  • Received:2005-12-08 Revised:2006-02-16 Published:2006-06-27
  • Contact: GAO Tao

Abstract: The molecule structures for the ground and low-lying states of He2+ and He2++ are calculated using the SAC/SAC-CI with the basis set CC-PV5Z. The analytical forms of potential energy function are least-squared-fitted from the potential energy and the corresponding spectroscopic data are derived out. For He2+, the obtained spectroscopic data of X2Σu+ are in well agreement with the experimental data and the results for the excited states 2Πu, 4Σu+, and 4Πg, are worked out for the first time. For He2++, the results indicate that only the ground state X1Σg+ and excited states 1Σg+, 1Σu+ among the nine calculated states are bound states. The spectroscopic constants corresponding to these three states are worked out, and the origin of the energy barriers in the ground states X1Σg+ energy curve has been explained using the avoided crossing rules of valence bond model.

Key words: Excited state, Potential function, Spectroscopic constants, He2+, He2++