Cross-relaxation between Kramers and non-Kramers ions by a quadrupole-electric-field interaction

A new mechanism is proposed for the cross-relaxation between Kramers ions and fast relaxing non-Kramers ions with gperpendicular to =0. It is postulated that the change in the quadrupole moment of the Kramers ion when a transition occurs causes an electric-field-induced transition to occur in the non-Kramers ion. Preliminary calculations are given for the Cr3+-Fe2+ system.