OPTICAL AND MAGNETOOPTICAL PROPERTIES OF PRSB

We present the results of a theoretical study for the interpretation o f the optical and magneto-optical spectra of PrSb. In particular, we a ddress the question of the assignment of the unexpectedly low optical and magneto-optical signals to the f2 --> f1d transition. We use two d ifferent approaches: the crystal-field approach, suitable for the Pr 4 f states assumed to be localized, and the band approach for the conduc tion electrons polarized by the 4f states. The two pictures are merged by the technique of a fixed 4f spin moment used to perform the spin-p olarized calculations for the conduction electrons. We calculate the 4 f spin moment mu4f(s) in the crystal-field ground state of Pr3+ includ ing the molecular-field correction lambdaM. From the local spin densit y approximation calculations we evaluate the molecular-field constant lambda, which agrees with the previous value, the interband conductivi ty, reflectivity, and the Kerr rotation angle for the conduction elect rons. On the basis of our model we find that the weak intensity of the optical and magneto-optical signal is ascribable essentially to elect ric dipole selection rules among crystal-field states. Finally, we int erpret the structure at congruent-to 1 eV in the off-diagonal conducti vity spectrum in terms of the f2 --> f1d transition. This is in agreem ent with two different reflectivity spectra.