Non-physical consequences of the Muffin-tin -- type intra-molecular potential

We demonstrate that in the frame of muffin-tin -- like potential non-physical peculiarities appear in molecular photoionization cross-sections and other characteristics of this process that are a consequence of ``jumps'' in the potential and discontinuous of its derivative at some radius. The role of the size of this ``jumps'' is illustrated by choosing three values of the size of potential ``jumps''. The result obtained are tightly connected to the studied previously effect of the influence of non-analytical behavior of the potential acting upon a particle $U(r)$as a function of $r$on its photoionization cross-section. In reality, such potential has to be an analytic in magnitude and first derivative function of $r$. Introduction of non-analytic features in model $U(r)$leads to non-physical features in the corresponding cross-section -- oscillations, additional maxima etc. It is demonstrated here in the frame of a model of hydrogen atom surrounded by a barrier that for reasonable values of it leads to non-physical oscillations that are almost as strong as physical oscillations in the two-atomic molecule photoionization cross-section.