Prolate non-collective-A rare shape phase in high spin state proton emitters 141–144Ho and 131–135Eu

Structural transitions in high spin states of deformed odd Z proton emitters Ho and Eu are studied in a theoretical framework using the deformed Nilsson potential and Strutinsky’s prescription combined with statistical theory of hot rotating nuclei. These proton emitters are found to exhibit shape transition to a rare prolate non-collective shape phase in excited high spin state which is caused directly by rotation at certain angular momentum values which creates a residual quantum shell effect. This phase exists only in a narrow domain bound by the two spin dependent very low critical temperatures. This unexpected prolate noncollective phase generated by rotation undergoes the expected transition to the oblate noncollective phase at higher angular momentum values. Phenomenon of shape coexistence with prolate and oblate non-collective shapes is also speculated in high spin state Eu.