Okumu, J.Morgan, G. J.2014-06-032014-06-032000-07Journal of Non-Crystalline Solids Volume 272, Issue 1, Pages 67–700022-3093http://ir-library.ku.ac.ke/handle/123456789/9758http://dx.doi.org/10.1016/S0022-3093(00)00227-1We have used the random phase model for the electronic wave-functions to calculate the imaginary part of the dielectric function and the magnitude of the third-order response, |χ3(ω)| using a model structure of a-Si containing 1728 atoms. We show that this simple calculation gives reasonable results for ε(ω) and furthermore, the behaviour of χ3(ω) is similar to more detailed theoretical calculations.enO110A200S180Article