Investigation of the alignment mechanism and loss of collectivity in Pm 135

High-spin excited states of 135 Pm have been investigated using the Ag-107(S-32, 2p2n) reaction at 145-MeV beam energy. Three negative-parity bands have been investigated up to similar to 9.0-, 7.6-, and 6.9-MeV excitation energies with spin parities (55/2(-)), (49/2(-)), and (47/2(-)) h, respectively. The experimental results have been interpreted using the triaxial projected shell model. It is shown that the observation of the parallel band structures can be explained in terms of crossing of two s bands with the yrast band, which is a rare phenomenon for an odd-A nucleus. Further, the lifetimes of levels in yrast band have been extracted using Doppler shift attenuation method. The evaluated B(E2) values of yrast states show the loss of collectivity at higher spin, attributed to the alignment process.