Electron paramagnetic resonance of the Van Vleck compound PrVO4 doped with Gd has been used to study the exchange and dipolar interactions of the Pr3+-Gd3+ pair. The Gd3+ electronic g shifts depend only on the diagonal components of these interactions. The pseudoaxial fields and the indirect superhyperfine interactions are functions of both diagonal and off-diagonal elements. From a combined measurement of all these interactions, both symmetric and antisymmetric exchange fields can be estimated. © 1980 The American Physical Society.