Behavior of the Low-lying Alternating-parity Energy Levels of the Rigid Asymmetric Rotator Depending on the Angular Variable of the Polar Coordinate

Recently, even–even nuclei with quadrupole and octupole deformations have been studied, taking into account the triaxiality of their shape. This approach allows one to simultaneously describe the alternating-parity spectrum of different bands of these nuclei. In this case, the values of the parameters of quadrupole and octupole triaxiality go beyond the traditional characteristic values of separate consideration of these deformations: \(\gamma _{\rm eff}\) (\(0\leq \gamma _{\rm eff}\leq \frac {\pi }{6}\)) and \(\eta _{\rm eff}\) (\(0\leq \eta _{\rm eff}\leq \frac {\pi }{2}\)). To identify the reasons for these differences, we studied the behavior of low-lying energy levels of a rigid asymmetric rotator with alternating parity depending on the angular variable of the polar coordinates \(\varepsilon _0\) for fixed values of the triaxiality parameters \(\gamma _{\rm eff}\) and \(\eta _{\rm eff}\). We determined the region of experimentally observed energy levels with alternating parity corresponding to the given values of the triaxial parameters \(\gamma _{\rm eff}\) and \(\eta _{\rm eff}\) for different values of the angular parameter \(\varepsilon _0\). Abstract Published by the Jagiellonian University 2025 authors