Quasiparticle-phonon model

Formalism of quasiparticle-phonon nuclear model for odd spherical nuclei is presented consistently. Taking into account exact commutation relations of quasiparticle- and phonon operators and anharmonic corrections for phonon excitations, equations are obtained for energies and structural coefficients of wave functions of excited states, comprising ''quasiparticle+phonon'' and ''quasiparticle+ two phonons'' components. Influence of different physical effects and phonon basis sire on fragmentation of the monoquasiparticle and ''quasiparticle+phonon'' states is studied. The role of the corrections to meet the Pauli principle requirement is studied. The description of the method of strength functions to calculate fragmentation of low-quasiparticle component strength is given. Iterative method of numerical solution of the equations obtained is described