maximum likelihood estimation (mle) method

In this paper, we have studied the spectral statistics of 101 even-even nuclei in the nearest neighbor spacing distribution framework. Sequences are prepared by using all the latest experimental data for 2 levels of considered nuclei in the 40 ≥ A≥198 mass region. The maximum likelihood estimation technique has been used to extract the Berry-Robnik distribution’s parameter which explores the regular or chaotic behavior of considered sequences. Sequences are classified as their mass, quadrupole deformation parameter, the energy ratio and the shell model configuration for the last protons and neutrons of all nuclei. Our results suggest a regular dynamics for these even mass nuclei. Also, the regularity is increased for light nuclei vis-a-vis heavier ones and also the deformed nuclei vis-a-vis spherical ones. Our results show a deviation of chaotic dynamics when the spins of proton levels are decreased or the spins of neutron levels are increased.