Hexadecapole states in deformed nuclei

The energies and wave functions of low-lying nonrotational hexadecapole states with Kπ=3+ and 4+ are calculated within the quasiparticle-phonon model for deformed even-even nuclei in the 158 ≤ A ≤ 188 range. The hexadecapole force constants κ0(44) and κ0(43) were fixed in the calculations. It is shown that at energies lower than 2 MeV in the Gd and Dy isotopes there are Kπ=4+ states with dominate two-quasiparticle components. In the Er, Yb and Hf isotopes there must be collective Kπ=3+ states with 1.2-1.6-MeV energies. In the Os isotopes there are collective Kπ=4+ states at 1.0-1.4 MeV. The calculated characteristics of the Kπ=4+ and 3+ states qualitatively agree with the available data. The influence of the hexadecapole forces on the first Kπ=2+ states is studied. It is shown tht the effect may be noticeable at certain values of the κ0(44)