The dynamical cluster-decay model (DCM) is developed further for the decay of hot and rotating compound nuclei (CN) formed in light heavy-ion reactions. The model is worked out in terms of only one parameter, namely the neck-length parameter, which is related to the total kinetic energy TKE(T ) or effective Q value Q eff (T ) at temperature T of the hot CN and is defined in terms of the CN binding energy and ground-state binding energies of the emitted fragments. The emission of both the light particles (LP), with A 4, Z 2, as well as the complex intermediate mass fragments (IMF), with 4 < A < 20, Z > 2, is considered as the dynamical collective mass motion of preformed clusters through the barrier. Within the same dynamical model treatment, the LPs are shown to have different characteristics compared to those of the IMFs. The systematic variations of the LP emission cross section σ LP and IMF emission cross section σ IMF calculated from the present DCM match exactly the statistical fission model predictions. A nonstatistical dynamical description is developed for the first time for emission of light particles from hot and rotating CN. The model is applied to the decay of 56 Ni * formed in the 32 S + 24 Mg reaction at two incident energies E c.m. = 51.6 and 60.5 MeV. Both the IMFs and average TKE spectra are found to compare resonably well with the experimental data, favoring asymmetric mass distributions. The LPs' emission cross section is shown to depend strongly on the type of emitted particles and their multiplicities.

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The dynamical cluster-decay model (DCM) is extended to a positive Q-value (Qout), heavy compound system 116Ba*, with complete angular momentum and charge dispersion effects included in it. The contributions due to both the light particles (LPs) and intermediate mass fragments (IMFs) are considered to give the total cross section. Interestingly, instead of the complete IMF spectrum observed for lighter systems such as 48Cr* and 56Ni*, here two small ‘windows of IMFs’ are predicted, one for light masses (2 ⩽ Z ⩽ 9) and another for the heavy mass end of symmetric and nearly symmetric fragments (14 ⩽ Z ⩽ 28), in agreement with the available data for the light mass ‘IMF window’ and its indications of possible extension to the heavier mass fragments. Within a non-statistical model description, the definition of phase space is found to be contained in the DCM definition of the ‘IMF window’ for the compound nucleus process. As in experiments, the calculated excitation functions are shown to put a limit on the minimum incident centre-of-mass energy required for the production of IMFs, and it will be of further interest to observe in experiments the predicted structures in the excitation functions of both the individual fragments, like for 12C decay, and the summed-up cross sections. Also, further measurements of the total kinetic energies of the fragments are called for.