Population of isomeric states in fusion and transfer reactions in beams of loosely bound nuclei near the Coulomb barrier

Abstract

The influence of the mechanisms of nuclear reactions on the population of 195m Hg and 197m Hg(7/2−), 198m Tl and 196m Tl(7+), and 196m Au and 198m Au(12−) isomeric nuclear states obtained in reactions induced by beams of 3He, 6Li, and 6He weakly bound nuclei is studied. The behavior of excitation functions and high values of isomeric ratios (δ m/δ g) for products of nuclear reactions proceeding through a compound nucleus and involving neutron evaporation are explained within statistical models. Reactions in which the emission of charged particles occurs have various isomeric ratios depending on the reaction type. The isomeric ratio is lower in direct transfer reactions involving charged-particle emission than in reactions where the evaporation of charged particles occurs. Reactions accompanied by neutron transfer usually have a lower isomeric ratio, which behaves differently for different direct-reaction types (stripping versus pickup reactions).