Weighted nonlinear regression analysis of a Sellmeier expansion: comparison of several nonlinear fits of CdS dispersion

Presented here is a modification in the adjustment for refractive-index nonlinear regression through a Sellmeier expansion. It is free of the deficiencies inherent in the earlier nonlinear method and notably improves the adjustment without excessively complicating the mathematical procedures. The method is applied to CdS with the object of comparing the results with those obtained previously. In this manner, the best adjustment has been found for CdS dispersion. It has also allowed a physical explanation of some adjustment parameters.