Systematics of alpha decay hindrance factors in doubly-even nuclei

In present work, we have calculated the hindrance factors of 182 even-even alpha emitters using Preston's formulation of alpha decay probabilities and presented HFs systematics of 1^- and 3^- states in reflection asymmetric even-even quadruple-octupole deformed nuclides (A~216-230). The calculated HFs of both 1^- and 3^- states decrease with reduction in neutron number and this decrease is attributed to onset of intrinsic reflection asymmetry. There is a trend reversal for 1^- states at N=132 (²¹⁸Ra) and N=134 (²²⁰Rn), which might be a possible indication of departure from static octupole deformation. Similarly, HFs systematics is discussed for ^224-230Th and ^232-236U isotopic chains along with 2⁺ states observed in daughter nuclei in N=132-146 isotonic chains. (author)