I'm trying to calculate silicon absorption coefficients using RajKanan model (1979) by MATLAB, however, I got incorrect results comparing to the one which shows in his curve. I'm wondering if anyone could help with this matter, or if someone had past experience with this subject. Also, what is the best model from the a quantum perspective and a classical one, that could fit with the experiments data of the silicon absorption coefficients?. The RajKanan paper is attached as well as the Matlab code. Thanks.