Okumu, J.Morgan, G.J.2015-06-022015-06-022001East African Journal of Science 3( I); 25-33 (200 I)1029-3221http://ir-library.ku.ac.ke/handle/123456789/12740Research ArticleWe have used the random phase model for the electronic wave functions to calculate the imaginary part of the dielectric function 82 (m) and the magnitude of the third harmonic generation, 11'3(OJ ~ using a model structure of a-Si containing 1728 atoms. We show that this simple calculation gives reasonable results for e(e) and furthermore the behaviour of .l. «(l). is similar to more detailed theoretical calculationsendisordered systemssemiconductorsoptical propertiesArticle