Fragmentation of Si clusters studied by a dynamical Hartree-Fock method at semi-empirical level

This study describes fragmentation of silicon clusters of size N less than or equal to 40. Fragmentation is produced by the increase of the kinetic energy E-k of the nuclear system and a time-dependent Hartree-Fock method, with a semi-empirical Hamiltonian is used for the evaluation of the transient ensuing the energy input. A typical channel of fragmentation has been observed which consists on the emission of small (from 1 to 5) groups of atoms. Due to these losses, the fragmentation remnants for N greater than or equal to 20 reach a size equal to 1/2-1/4 of the original one. These trends are in agreement with the experimental ones. Furthermore the critical energies obtained from fragmentation calculations are discussed in the light of the binding energies evaluated for the stationary state.