Electronic configuration of Mn ions in the $\pi$-d molecular ferromagnet   $\beta$-Mn phthalocyanine studied by soft x-ray magnetic circular dichroism
  We have studied the electronic structure of the molecular ferromagnet $\beta$-Mn phthalocyanine ($\beta$-MnPc) in a polycrystalline form, which has been reported to show ferromagnetism at T$<$8.6 K, by x-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD). From the experimental results and subsequent cluster-model calculation, we find that the ferromagnetic Mn ion in $\beta$-MnPc is largely in the $^4$$E$$_g$ ground state arising from the ($e$$_{g}$)$^3$($b$$_{2g}$)$^1$($a$$_{1g}$)$^1$ [($d_{xz,yz}$)$^3$($d_{xy}$)$^1$($d_{z^{2}}$)$^1$] configuration of the Mn$^{2+}$ state. Considering that the highest occupied molecular orbital (HOMO) of MnPc with the $^4$$E$$_g$ ground state originates from the $a$$_{1g}$ orbital of the Mn$^{2+}$ ion, it is proposed that $a$$_{1g}$-$a$$_{1g}$ exchange coupling via the $\pi$ orbitals of the phthalocyanine ring plays a crucial role in the ferromagnetism of $\beta$-MnPc. 
T. Kataoka, Y. Sakamoto, Y. Yamazaki, V. R. Singh, A. Fujimori, Y.   Takeda, T. Ohkochi, S.-I. Fujimori, T. Okane and Y. Sai...
cond-mat.mtrl-sci