Phenomenological formula for α-decay half-lives of heaviest nuclei

A simple phenomenological formula for description of a-decay half-lives T alpha of heavy (above Pb-208) and superheavy nuclei is proposed. The formula, expressing T-alpha as a function of the decay energy Q(alpha), has five adjustable parameters: three to describe even-even nuclei and two for accounting for effects of an odd proton and an odd neutron. The formula allows one to describe measured values of T-alpha of 61 even-even nuclei roughly within a factor of 1.3, 45 odd-even nuclei within a factor of 2.1, 55 even-odd nuclei within a factor of 3.2 and 40 odd-odd nuclei within a factor of 4.0, on the average, when measured values of Q(alpha) are taken. Results of its use are compared with those of other formulae. Effects of various changes in the formula are discussed.