A full quantum mechanical treatment of the atomic interaction with the electromagnetic vacuum and the reflecting evanescent-wave inside a hollow fiber is applied to obtain analytical expressions for both the radiation pressure exerted on the atoms under reflection and the van der Waals energy interaction. We show that both effects are originated in the interaction with the evanescent-wave, have its intensity radial dependence and depend on the evanescent-wave detuning in a way other than suggested by heuristic arguments. Through an analytical approach we discuss the general characteristics of the solutions of the Schrodinger wave equation and give expressions for the threshold values of laser detuning and intensity required for modal propagation.