Excitation energy equilibration in damped ${}_{}{}^{139}{}_{}{}^{}\mathrm{Ar}$ collisions at 15 MeV per nucleon

Energy and angular distributions of neutrons emitted in coincidence with projectile-like fragments from the damped reaction ${}_{}{}^{139}{}_{}{}^{}\mathrm{La}$${+}^{40}$Ar at a bombarding energy of 600 MeV have been measured. Components corresponding to sequential emission from two fully accelerated reaction fragments as well as preequilibrium neutron emission have been separated as a function of energy loss and fragment atomic number. The deduced division of total excitation energy between the reaction partners is very well described by the one-body nucleon-exchange model for all energy losses. The data provide no evidence for correlations between the excitation energy division and the measured projectile-like fragment atomic number.