Spin Polarization Effect of Ni2 Molecule

The density functional（B3P86）method has been used to optimize the structure of Ni2 molecule. Results show that the ground state for Ni2 molecule is 5 multiple state，not 1 multiple state and 3 multiple state the literatures concluded. That shows the spin polarization effect of Ni2 molecule of transition metal elements for the first time. They take 1 multiple state and 3 multiple state as the ground state of the Ni2 molecule because the minimal energy value of 1 multiple state，3 multiple state and 5 multiple state of Ni2 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 Ni2 molecule is 5 multiple state，which shows the spin polarization effect of Ni2 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 Ni2 molecule reduces to the minimum. It shows that the effect of parallel spin of Ni2 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 Ni2 molecule are also derived. Dissociation energy of the ground state Ni2 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 f2，f3 and f4 are 1.1901 aJ / nm2，-5.8723 aJ/nm3，21.2505 aJ/nm4 respectively.