Absolute Infrared Intensity Measurements in Thin Films

A theoretical investigation has been made of the errors which will be incurred if reflection effects (including multiple reflections) are neglected in making absolute (absorption) intensity measurements on thin films of pure liquids and solids. The results are presented in a series of figures for a number of typical experimental situations as a function of two generalized parameters. These figures permit an estimation of the error for any specific case. It is found that the error can be quite appreciable for some experimentally realistic situations. Since a computer program has been written to do the calculations, the authors are willing to run specific cases upon request.