Tidal wave in ¹⁰²Pd: An extended five-dimensional collective Hamiltonian description

The five-dimensional collective Hamiltonian based on the covariant density functional theory is applied to investigate the observed tidal wave mode in the yrast band of $^{102}$Pd. The energy spectra, the relations between the spin and the rotational frequency, and the ratios of $B(E2)/\mathcal{J}(I)$ in the yrast band are well reproduced by introducing the empirical $ab$ formula for the moments of inertia. This $ab$ formula is related to the fourth order effect of collective momentum in the collective Hamiltonian. It is also shown that the shape evolution in the tidal wave is determined microscopically by the competition between the rotational kinetic energy and the collective potential in the framework of the collective Hamiltonian.