Spin polarization effect of Ni2 molecule

The density functional theory (DFT) method (b3p86) of Gaussian 03 isused to optimize the structure of the Ni₂ molecule. The resultshows that the ground state for the Ni₂ molecule is a5-multiple state, symbolising a spin polarization effect existing inthe Ni₂ molecule, a transition metal molecule, but no spinpollution is found because the wave function of the ground statedoes not mingle with wave functions of higher-energy states. So theground state for Ni₂ molecule, which is a 5-multiple state, isindicative 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 electronsoccupy different spatial orbitals so that the energy of the Ni₂molecule is minimized. It can be concluded that the effect ofparallel spin in the Ni₂ molecule is larger than that of theconjugated molecule, which is obviously related to the effect ofelectron d delocalization. In addition, the Murrell-Sorbie potentialfunctions with the parameters of the ground state and other statesof the Ni₂ molecule are derived. The dissociation energyD_e for the ground state of the Ni₂ molecule is1.835eV, equilibrium bond length R_e is 0.2243,nm,vibration frequency omega_e is 262.35cm^-1. Itsforce 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 Ni₂molecule omega_echi_e, B_e and alpha_e are 1.6315cm^-1, 0.1141,cm^-1, and8.0145x10^-4cm^-1 respectively.