High-spin states and nuclear shape of W and Os isotopes. Are there non-axial nuclei

The non-axiality of nuclei located at the end of rare-earth elements region of the Periodic tahle of elements is discussed. Quasiparticle excitations in a rotating nucleus are a convenient means to study nuclear deformation. It is shown, that the nuclear non-axiality must strongly effect the high-spin rotational states. On the example of rare earth isotopes the effect of nuclear deformation on the behaviour of quasiparticle terms is demonstrated. There is no evidence yet of the W and Os nuclei nonaxiality, although the average value of γ-deformation in the ground state of even-even nuclei can be different from zero. However, the spectrum of the nuclei is evidently more complicated than the nonaxial rotator spectrum