Abstract :
The emissions of projectile-like fragments from light and medium heavy ion reactions have been discussed. In the case of certain nuclear reactions, such as, 24Mg+16O, 28Si+12C etc. among light heavy ion systems and 16O+89Y, 16O+93Nb etc. among medium heavy ion systems, both a 1/sinθc.m. angular distribution for projectile-like fragments and strong entrance channel dependence favoring breakup into the entrance channel with large excitation energy have been observed. We think these observations imply the formation of a long-lived orbiting dinuclear complex where the nuclei maintain their identities and nucleon exchange between them is highly suppressed. The analysis of fragment spectra show that the projectile-like fragments coming from such an orbiting dinuclear complex give significantly lower temperature compared to that of the respective compound nucleus.
