On the preequilibrium emission of clusters

An approach for the description of the preequilibrium emission of light composite particles in the framework of the exciton model is proposed. The description is analogous to the Iwamoto‐Harada (I–H) model in which formation factors (FF) of clusters are obtained and the possibility of pick up process is taken into account. In the model proposed phase‐space volume corresponding some arbitrary type of cluster with fixed excitation energies of nucleons picked up below and above Fermi Surface (FS) is calculated. This allows us to obtain the correct distribution of excitation energy between particle and hole degrees of freedom in the final state density of system: compound nucleus‐cluster. The simple factorized form of the final state density of system can be obtained by introducing the average values of excitation energy of cluster constituent particles. The result of I–H treatment is valid only if we neglect the hole energy of picked up m particles, and thus it results in the overestimation of final states density and correspondingly overestimates cross‐sections in comparison with the approach proposed. The numerical calculations of modified formation factors (MFF) of alpha particle and tritium are performed.