Angular momentum transfer in the deep inelastic reactions of 237 MeVAr40withY89

The mechanisms of strongly damped collisions of 237 MeV ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}$ with ${}_{}{}^{89}{}_{}{}^{}\mathrm{Y}$ have been studied by measurements of the energy distributions and angular distributions of the identified products. Average gamma-ray multiplicities $〈M_{\gamma }〉$ and average gamma-ray energies $〈E_{\gamma }〉$ have been measured for these reactions. Empirical relationships between $〈M_{\gamma }〉$ and the average angular momenta were employed to determine the angular momenta of the primary fragments produced in the reactions. The angular momentum transfer in the strongly damped collisions increases with increasing angle of emission of the projectile-like fragment. Evidence is presented that for the lowest partial waves contributing to strongly damped collisions the condition of rigid rotation is achieved. The use of such reactions to select nuclei of particular $〈J〉$ is discussed.