  The models of permanent lattice defect formation in rare-gas solids are
discussed with a focus on a point defect formation in solid Ar. The processes
of large-scale atomic displacements induced by electronic excitations were
studied using the selective vacuum ultraviolet spectroscopy method. The
coexistence of intrinsic excitonic mechanism and extrinsic Rydberg state
induced excited-state mechanism of Frenkel defect formation was found.
