Abstract
The authors have obtained strength functions from the resonance parameters of elastic alpha scattering on target nuclei with mass numbers 12<or=A<or=40. First they made a comparison between these experimental strength functions and the predictions of an optical model. In this model both the real and the imaginary potential have Woods-Saxon shape, and the parameters are given by the systematics of Gupta and Murthy (1982) and Shridhar (1984) et al. From this comparison the imaginary potential seems to be overestimated, while the real part is mostly in better agreement with the experimental data. Then they determined potential parameters from the experimental strength functions for the 12C+ alpha and 16O+ alpha systems. Such parameters were deduced both with the assumption of a Woods-Saxon-type potential and with the bell-shaped potential of the cluster mode given by Buck et al. (1977). As for the 12C+ alpha system, the strength distributions are in good agreement with the picture of the fragmentation of a single-particle resonance in each partial wave while in the 16O+ alpha case the agreement is not so good.