Exchange interactions in Ti2Cl93- and the magnetic susceptibility tensor

Calculated exchange interactions in Ti2Cl93- by the CASSCF method are combi ned with parametric expressions of metal-centred spin-orbit coupling and Ze eman splittings to predict the temperature dependence of the magnetic susce ptibility tensor between 0 and 300 K. The results correctly reproduce the e xperimental anisotropy at 0 K, the onset of the magnetization and the slope of the susceptibility curve. The discussion confronts the theoretical trea tment with existing semi-empirical magnetic models. A (1)A(1)'(a x a) --> 1 E'(a x e) assignment is proposed for the weak absorption feature in the inf rared reflectance spectrum.