Alternative analytical forms of the Fuchs-Sondheimer function

Starting from the Cottey conduction model and its extension, it is shown that the Fuchs-Sondheimer functions can be approximated by the extended Cottey function at any reduced thickness, provided that the specular electronic reflection coefficient, p, takes values larger than 0.31. Whatever the values of p and the film thickness be an analytical formulation (in the form of the Cottey function) is proposed for an accurate approximation of the Fuchs-Sondheimer function. Moreover, it is suggested that the scattering processes defined in the Fuchs-Sondheimer model have no interaction.