Is there evidence of simple relationship among measured yrast energies in even-even nuclei?

We benefit often by studying particular nuclear properties in terms of simple variables over the wide span of the chart of nuclides. A well-known such example for the ground state is the semi-classical mass formula. But, there have seldom appeared similar studies on observables concerning the excited states of nuclei. In this work, we collect measured yrast energies in even-even nuclei and test whether there exists any simple relationship among them.