SPIN EQUILIBRIUM OF 6A1 ↔ 2T2 IN TRIS (MONOTHIO-β-DIKETONATO) IRON (III) J. Akashi, K. Endo and H. Sano J. Phys. Colloques, 40 C2 (1979) C2-405-C2-407 DOI: 10.1051/jphyscol:19792141