Spin polarization effect for Os₂ molecule

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 10^2aJ\cdotnm^-2, -14.3425\times 10^3aJ\cdotnm^-3 and 50.5792\times 10^4aJ\cdotnm^-4 respectively. The other spectroscopic data for the ground state of Os_2 molecule \omega_\rm e\chi_\rm e, B_\rm e and \alpha_\rm e are 0.4277cm^-1, 0.0307cm^-1 and 0.6491\times 10^-4cm^-1 respectively.