Ni_2分子的自旋极化效应

Spin Polarization Effect of Ni_2 Molecule

采用Gaussian98程序中B3P86密度泛函 (DFT)方法 ,对Ni2 分子进行了优化 ,得到该分子基态为 5重态 ,并且首次发现了过渡金属中Ni2 分子存在自旋极化效应 .计算得到了该分子的力学常数、光谱数据及势能函数 .计算结果表明 :该分子基态离解能为 1.835eV ,平衡键长为 0 .2 2 4 3nm ,谐振频率为 2 6 2 .35cm-1,二阶、三阶、四阶力学常数分别为 1.190 1aJ/nm2 、- 5 .872 3aJ/nm3 及 2 1.2 5 15aJ/nm4,得到了Ni2 分子的Murrell Sorbie势能函数 .

The density functional (B3P86) method has been used to optimize the structure of Ni 2 molecule. Results show that the ground state for Ni 2 molecule is 5 multiple state, not 1 multiple state and 3 multiple state the literatures concluded. That shows the spin polarization effect of Ni 2 molecule of transition metal elements for the first time. They take 1 multiple state and 3 multiple state as the ground state of the Ni 2 molecule because the minimal energy value of 1 multiple state, 3 multiple state and 5 multiple state of Ni 2 molecule are very close to each other. Meanwhile, we have not found out any spin pollution and the ground state wave function doesn′t mingle with wave function with higher energy state. The result shows that the ground state for Ni 2 molecule is 5 multiple state, which shows the spin polarization effect of Ni 2 molecule of transition metal elements. That is, there exist 4 parallel spin electrons, at this time; the number of the non-conjugated electron is the most. These electrons occupy different spacious tracks so that the energy of Ni 2 molecule reduces to the minimum. It shows that the effect of parallel spin of Ni 2 molecule is larger than the effect of the conjugated molecule. It is obviously related to the effect of electron d delocalization. The Murrell-Sorbie potential function with the parameters for ground state for Ni 2 molecule are also derived. Dissociation energy of the ground state Ni 2 molecule is 1.835 eV, the equilibrium bond length is 0.2243 nm, and the vibration frequency is 262.35 cm -1. The force constants f 2, f 3 and f 4 are 1.1901 aJ/nm2, -5.8723 aJ/nm3, 21.2505 aJ/nm4 respectively.