90° excitation functions for elastic scattering of 28Si+16O and 28Si+12C

The gross structures in the excitation functions for elastic scattering of ²⁸Si+¹⁶O and ²⁸Si+ ¹²C, measured at 90°, where only even partial waves contribute, are found to be anti-correlated with those at 180°. Excitation functions at both angles, including the enhanced gross structure at 180°, can be reproduced by calculations using a potential which attracts odd partial waves more than even partial waves.