orbital energies                                                                                                     
   $\Delta_{\textrm{M}\sigma}^0$                                    879 meV            522 meV               476 meV               181 meV
    $\Delta_{\textrm{M}\pi}^0$                                        -193               -612                  -636                  -377
                                                                                                                              
        orbital occupancies                                                                                                   
   $\bar{n}_{\textrm{M}\sigma}$                                       0.02               0.03                  0.09                  0.86
      $\bar{n}_{\textrm{L}}$                                          1.16               1.50                  1.47                  1.15
     $\bar{n}_{\textrm{M}\pi}$                                        1.66               1.97                  1.97                  1.85

\[table1\]

Fitting to first-principles band calculations {#subsec2-2}
---------------------------------------------

The tight-binding parameters are obtained by a numerical fitting to first-principles band structures for the nonmagnetic state. In Fig. \[fig2\], we show the bands near $\epsilon_{\rm F}$, together with the fitted tight-binding dispersions. The four bands originate from the four MO, or equivalently, the four fMO; The unit cell consists of one molecule. As for \[Au(tmdt)$_2$\], calculations were performed for both room-$T$ and low-$T$ (9 K) structures determined experimentally, due to the indication of a structural variation upon cooling [@Zhou_2009IC], as noted above. In the calculations for \[Ni(tmdt)$_2$\] and \[Cu(tmdt)$_2$\], the room-$T$ structure parameters are used.

One can see that the top band in \[Ni(tmdt)$_2$\] and the bottom band in \[Au(tmdt)$_2$\] are separated from the others. This is the reason we previously used three-band fits (two kinds of fMO) [@Seo_2008JPSJ]. On the other hand, in \[Cu(tmdt)$_2$\], all four bands are overlapping, requiring a four-band fit for a reasonable agreement with the first-principles band structure. Note that the total band 