Modelling the optical constants of GaAs: excitonic effects at E-1, E-1+Delta(1) critical points

Calculation of the optical constants of GaAs is presented. In this work we do not take into account excitonic effects at E-1 and E-1 + Delta(1) critic al points. In such a manner, fewer adjustable model parameters are required and the term with dubious physical interpretation describing excitons at E -1 and E-1 + Delta(1) is left out. Reasons for exclusion of this term are d iscussed in detail. In spite of the fewer terms describing the contribution s of different transitions to the dielectric function, we obtain excellent agreement with experimental data over the entire 0.125-6 eV range, with rel ative rms error for the refractive index equal to 2.6%.