中国物理B ›› 2008, Vol. 17 ›› Issue (12): 4498-4503.doi: 10.1088/1674-1056/17/12/028
阎世英1, 朱正和2
Yan Shi-Ying (阎世英)a, Zhu Zheng-He (朱正和)b
摘要: The density functional theory (DFT) method (b3p86) of Gaussian 03 is used to optimize the structure of the Ni2 molecule. The result shows that the ground state for the Ni2 molecule is a 5-multiple state, symbolising a spin polarization effect existing in the Ni2 molecule, a transition metal molecule, but no spin pollution is found because the wave function of the ground state does not mingle with wave functions of higher-energy states. So the ground state for Ni2 molecule, which is a 5-multiple state, is indicative of spin polarization effect of the Ni2 molecule, that is, there exist 4 parallel spin electrons in Ni2 molecule. The number of non-conjugated electrons is greatest. These electrons occupy different spatial orbitals so that the energy of the Ni2 molecule is minimized. It can be concluded that the effect of parallel spin in the Ni2 molecule is larger than that 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 of the ground state and other states of the Ni2 molecule are derived. The dissociation energy De for the ground state of the Ni2 molecule is 1.835eV, equilibrium bond length Re is 0.2243\,nm, vibration frequency \omegae is 262.35cm-1. Its force constants f2, f3 and f4 are 1.1901aJ.nm2, --5.8723aJ.nm-3, and 21.2505\,aJ.nm-4 respectively. The other spectroscopic data for the ground state of the Ni2 molecule \omegae\chie, Be and \alphae are 1.6315cm-1, 0.1141\,cm-1, and 8.0145x10-4cm-1 respectively.
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