HIGH SPIN-LOW SPIN TRANSITION IN SUBSTITUTED PHENANTHROLINE COMPLEXES OF IRON (II) J. FLEISCH, P. GÜTLICH, K.M. HASSELBACH et W. MÜLLER J. Phys. Colloques, 35 C6 (1974) C6-659-C6-662 DOI: 10.1051/jphyscol:19746145