Nonaxial octupole deformations and shell phenomena - art. no. 034303

Manifestations of pronounced shell effects are found when combining nonaxia l octupole deformations with a three-dimensional harmonic oscillator model. The contributions of the main classical periodic orbits of this intrinsica lly chaotic three degrees of freedom system are obtained from a frequency a nalysis. An adiabatic approximation based on the removal of resonance metho d yields explicit expressions far winding numbers from which the quantum sp ectrum can be predicted. The shell structure obtained from this quadrupole +octupole combination turns out to be equivalent to the shell structure of a plain but more strongly deformed quadrupole potential far about the first 100 levels. [S0556-2813(99)07708-0].