Energy levels, electric dipole transition probabilities and oscillator strengths in five times ionized silicon have been calculated in intermediate coupling. The present calculations were carried out with the general purpose atomic structure program superstructure. The relativistic corrections to the non-relativistic Hamiltonian are taken into account through the Breit-Pauli approximation. We have also introduced a semi-empirical correction [term energy corrections (TEC)] for the calculation of the energy levels. These atomic data are used to provide semiclassical electron-, proton- and ionized helium-impact linewidths and shifts for 15 Si VI multiplet. Calculated results have been used to consider the influence of Stark broadening for DO white dwarf atmospheric conditions.