First forbidden beta decay in149Pm

The 786 keV beta-286keV gamma angular correlation in the ground state decay of149Pm is measured for the first time, using the conventional slow-fast scintillation assembly. Integral correlation results characterize the involved beta transition to be of first-forbidden non-unique type. The present results combined with the other experimental parameters, strongly support a 9/2− spin-parity character to the 286 keV level in149Sm. The energy independence of the reduced correlation coefficient as found in this work shows the validity ofξ-approximation for the 786 keV beta transition in149Pm and is also consistent with the logft value and spectrum shape reported by earlier authors.