中国物理B ›› 2004, Vol. 13 ›› Issue (12): 2053-2057.doi: 10.1088/1009-1963/13/12/013

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Spin polarization effect for Tc2　molecule

朱正和1, 阎世英2   

  1. (1)Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China; (2)Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China; Department of Physics, College of Science and Engineering, Qingdao University, Qingdao 266071, China
  • 收稿日期:2004-05-18 修回日期:2004-08-23 出版日期:2004-12-17 发布日期:2005-03-17

Spin polarization effect for Tc2 molecule

Yan Shi-Ying (阎世英)ab, Zhu Zheng-He (朱正和)a   

  1. a Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China; b Department of Physics, College of Science and Engineering, Qingdao University, Qingdao 266071, China
  • Received:2004-05-18 Revised:2004-08-23 Online:2004-12-17 Published:2005-03-17

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摘要： Density functional method (DFT) (B3p86) of Gaussian98 has been used to optimize the structure of the Tc_2 molecule. The result shows that the ground state for Tc_2 molecule is an 11-multiple state and its electronic configuration is {}^{11}Σ_g^-, which shows the spin polarization effect of Tc_2 molecule of a transition metal element for the first time. Meanwhile, we have not found any spin pollution because the wavefunction of the ground state does not mingle with wavefunctions of higher energy states. So, that the ground state for Tc_2 molecule is an 11-multiple state is indicative of the spin polarization effect of Tc_2 molecule of a transition metal element: that is, there exist 10 parallel spin electrons. The non-conjugated electron is greatest in number. These electrons occupy different spacious tracks, so that the energy of Tc_2 molecule is minimized. It can be concluded that the effect of parallel spin of the Tc_2 molecule is larger than the effect of the conjugated molecule, which is obviously related to the effect of electron d delocalization. In addition, the Murrell--Sorbie potential functions with the parameters for the ground state {}^{11}Σ_g^- and other states of Tc_2 molecule are derived. Dissociation energy D_e for the ground state of T_{c2} molecule is 2.266eV, equilibrium bond length R_e is 0.2841nm, vibration frequency ω_e is 178.52cm^{-1}. Its force constants f_2, f_3, and f_4 are 0.9200aJ·nm^{-2}, --3.5700aJ·nm^{-3}, 11.2748aJ·nm^{-4} respectively. The other spectroscopic data for the ground state of Tc_2 molecule ω_eχ_e, B_e, α_e are 0.5523cm^{-1}, 0.0426cm^{-1}, 1.6331×10^{-4}cm^{-1} respectively.

关键词: Tc2, spin polarization, density functional theory, potential function

Abstract: Density functional method (DFT) (B3p86) of Gaussian98 has been used to optimize the structure of the Tc$_2$ molecule. The result shows that the ground state for Tc$_2$ molecule is an 11-multiple state and its electronic configuration is $^{11}$Σ$_{\rm g}^-$, which shows the spin polarization effect of Tc$_2$ molecule of a transition metal element for the first time. Meanwhile, we have not found any spin pollution because the wavefunction of the ground state does not mingle with wavefunctions of higher energy states. So, that the ground state for Tc$_2$ molecule is an 11-multiple state is indicative of the spin polarization effect of Tc$_2$ molecule of a transition metal element: that is, there exist 10 parallel spin electrons. The non-conjugated electron is greatest in number. These electrons occupy different spacious tracks, so that the energy of Tc$_2$ molecule is minimized. It can be concluded that the effect of parallel spin of the Tc$_2$ molecule is larger than the effect of the conjugated molecule, which is obviously related to the effect of electron d delocalization. In addition, the Murrell--Sorbie potential functions with the parameters for the ground state $^{11}$Σ$_{\rm g}^-$ and other states of Tc$_2$ molecule are derived. Dissociation energy $D_{\rm e}$ for the ground state of $T_{\rm c2}$ molecule is 2.266eV, equilibrium bond length $R_{\rm e}$ is 0.2841nm, vibration frequency $\omega_{\rm e}$ is 178.52cm$^{-1}$. Its force constants $f_2$, $f_3$, and $f_4$ are 0.9200aJ$\cdot$nm$^{-2}$, --3.5700aJ$\cdot$nm$^{-3}$, 11.2748aJ$\cdot$nm$^{-4}$ respectively. The other spectroscopic data for the ground state of Tc$_2$ molecule $\omega_{\rm e}\chi_{\rm e}$, $B_{\rm e}$, $\alpha_{\rm e}$ are 0.5523cm$^{-1}$, 0.0426cm$^{-1}$, $1.6331\times10^{-4}$cm$^{-1}$ respectively.

Key words: Tc2, spin polarization, density functional theory, potential function

中图分类号: 

  • 31.15.E-
33.15.Fm (Bond strengths, dissociation energies) 33.15.Dj (Interatomic distances and angles) 33.15.Mt (Rotation, vibration, and vibration-rotation constants) 34.20.Gj (Intermolecular and atom-molecule potentials and forces)