Alpha particle clustering in f-p shell nuclei using the (7Li,t) reaction

Angular distributions for the (7Li,t) reaction to the ground and first excited states of the residual nuclei have been measured at E(7Li) = 34 MeV on 40Ca, 44Ca, 56Fe, 58Ni, and 60Ni targets to measure α clustering probabilities in these nuclei. Also, 7Li elastic scattering angular distributions were measured. Exact finite-range distorted-wave Born-approximation (DWBA) calculations were performed and compared to the (7Li,t) reaction measurements to extract alpha spectroscopic factors. The absolute alpha specroscopic factors were found to be highly sensitive to the alpha-plus-target-bound-state parameters. It was found that the (7Li,t) cross sections on the nuclei measured are approximately 2 to 3 times smaller than the (6Li,d) cross sections. A reanalysis of existing (6Li,d) reaction data in this mass region was performed and it was found that 6Li optical model parameters that describe both 6Li elastic scattering and single-nucleon-transfer reactions also give good fits to data when used with DWBA calculations for the (6Li,d) reaction. The relative alpha spectroscopic factors obtained from this present analysis were also in agreement with the (7Li,t) alpha spectroscopic factors. The relative alpha spectroscopic factors determined in this work show an increase in alpha clustering for targets with Z and N greater than or equal to 28, relative to 40Ca