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Spin polarization effect for molecule Ta2
谢安东
2006 (2):
324-328.
doi: 10.1088/1009-1963/15/2/016
摘要
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Density functional theory (DFT) (B3p86) has been used to optimize the
structure of the molecule Ta$_2 $. The result shows that the ground
state of molecule Ta$_2 $ is a 7-multiple state and its electronic
configuration is $^{7}\Sigma _{u}^{ + }$, which shows the spin
polarization effect for molecule Ta$_2 $ of transition metal elements for
the first time. Meanwhile, spin pollution has not been found because the
wavefunction of the ground state does not mix with those of higher states.
So, the fact that the ground state of molecule Ta$_2 $ is a 7-multiple state
indicates a spin polarization effect of molecule Ta$_2 $ of the transition metal
elements, i.e. there exist 6 parallel spin electrons and the non-conjugated
electrons are greatest in number. These electrons occupy different space
orbitals so that the energy of molecule Ta$_2 $ is minimized. It can be
concluded that the effect of parallel spin of the molecule Ta$_2$ is larger
than the effect of the conjugated molecule, which is obviously related to
the effect of d-electron delocalization. In addition, the Murrell--Sorbie
potential functions with parameters for the ground state $^{7}\Sigma
_{u}^{ + }$ and other states of the molecule Ta$_2$ are derived. The
dissociation energy $D_\e$, equilibrium bond length $R_\e$ and vibration
frequency
$\omega_\e$ for the ground state of molecule Ta$_2$ are 4.5513eV,
0.2433\,nm
and 173.06\,cm$^{-1}$, respectively. Its force constants $f_2$, $f_3$ and
$f_4$ are 1.5965$\times $10$^{2}$aJ$\cdot$nm$^{-2}$, --6.4722$\times
$10$^{3}$aJ$\cdot$nm$^{-3}$ and 29.4851$\times
$10$^{4}$aJ$\cdot$nm$^{-4}$,
respectively. Other spectroscopic data $\omega_{\e}$ $\chi_{\e}$,
$B_{\e}$ and $\alpha_{\e}$ for
the ground state of Ta$_2 $ are 0.2078\,cm$^{-1}$, 0.0315
cm$^{-1}$ and 0.7858$\times $ 10$^{-4}$\,cm$^{-1}$,
respectively.
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