The authors consider some specific features of the 4f wavefunction collapse in the rare-earth elements and its effect on all nf electrons with n>4. The results of this investigation are used in Dirac-Fock self-consistent field calculations for lanthanum (6s²nf_5/2) and europium (6s²4f_5/2⁶nf_7/2) with n=4, 5 and 6. The exchange interaction is shown to play an important role in the formation of 'collapsed' and 'blown' states of these atoms with n=4. A calculation has been made of the contribution to the total energy of an atom coming from the lanthanum 4f_5/2 and europium 4f_7/2 electrons in the 'collapsed' and 'blown' states of these atoms. The europium nf_7/2 electrons with n=5 and n=6 are shown to be localised in the outer well of the effective potential, their one-electron parameters being close to those of the 5f and 6f electrons in the Coulomb field, respectively. At the same time in lanthanum with n=5 and n=6, the nf_5/2 electrons can be found with a high probability in either of the effective potential wells.