中国物理B ›› 2005, Vol. 14 ›› Issue (9): 1808-1812.doi: 10.1088/1009-1963/14/9/021
阎世英1, 朱正和1, 谢安东2, 傅依备3
Xie An-Dong (谢安东)ab, Yan Shi-Ying (阎世英)a, Zhu Zheng-He (朱正和)a, Fu Yi-Bei (傅依备)c
摘要: Density functional Theory (DFT) (B3p86) of Gaussian03 has been used to optimize the structure of Os$_2$ molecule. The result shows that the ground state for Os$_2$ molecule is 9-multiple state and its electronic configuration is $^{9}\Sigma _{\rm g}^{+}$, which shows spin polarization effect of Os$_2$ molecule of transition metal elements for the first time. Meanwhile, we have not found any spin pollution because the wavefunction of the ground state does not mingle with wavefunctions with higher energy states. So, the fact that the ground state for Os$_2$ molecule is a 9-multiple state is indicative of spin polarization effect of Os$_2$ molecule of transition metal elements. That is, there exist 8 parallel spin electrons. The non-conjugated electron is greatest in number. These electrons occupy different spacious tracks, so that the energy of Os$_2$ molecule is minimized. It can be concluded that the effect of parallel spin of Os$_2$ 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 $^{9}\Sigma _{\rm g}^{+}$ and other states of Os$_2$ molecule are derived. Dissociation energy $D_\e$ for the ground state of Os$_2$ molecule is 3.3971eV, equilibrium bond length Re is 0.2403nm, vibration frequency $\omega _\e $ is 235.32cm$^{-1}$. Its force constants $f_2$, $f_3$, and $f_4$ are 3.1032$\times $10$^{2}$aJ$\cdot$nm$^{-2}$, $-14.3425\times $10$^{3}$aJ$\cdot$nm$^{-3}$ and 50.5792$\times $10$^{4}$aJ$\cdot$nm$^{-4 }$ respectively. The other spectroscopic data for the ground state of Os$_2$ molecule $\omega_{\e}\chi_{\e}$, $B_{\e}$ and $\alpha_{\e}$ are 0.4277cm$^{-1}$, 0.0307cm$^{-1}$ and 0.6491$\times $ 10$^{-4}$cm$^{-1}$ respectively.
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