3α-cluster structure of the 0+ states in 12C and the effective α-α interactions

The 0+ states of 12C are considered within the framework of the microscopic three-α-cluster model. The main attention is paid to accurate calculation of the width of the extremely narrow near-threshold 02+ state which plays a key role in stellar nucleosynthesis. It is shown that the 02+-state decays by means of the sequential mechanism 12C→α+8Be→3α. Calculations are performed for a number of effective α-α potentials which are chosen to reproduce both energy and width of 8Be. The parameters of the additional three-body potential are chosen to fix both the ground and excited state energies at the experimental values. The dependence of the width on the parameters of the effective α-α potential is studied in order to impose restrictions on the potentials