In this work, we derive analytical solutions for static structure factor for homogeneous and isotropic solution composed of two components interacting with each other via simple van der Waals potential which isinversely proportional to the sixth power of the distance between the two components. We assume that the first component is the solvent and the second component is the dissolved material which has low concentration or density in comparison to the concentration of the solvent, i.e. dilute solution, which is common for macromolecular fluids. The presented solution is obtained using direct and inverse Fourier transforms in solving Ornstein–Zernike equations(OZE) for multicomponent systems. We calculated isothermal compressibilities as a function of concentration and comparison with other simulation and theoretical results are presented. We believe that the presented solution can be useful in studying biomolecular fluids and other soft matter fluids.

A comment on an article by Khater et al published in Pramana – J. Phys. 90: 59 (2018) is presented here. We represent two quotes on the article, the two quotes about the space-dependent fractional Schrödinger equation type and about one of the constants used by the authors.

A numerical formula is derived which gives solutions of the fractional Schrödinger equation in time-independent form in the case of Coulomb potential using Riemann–Liouville definition of the fractional derivative and the quadrature methods. The formula is applied for electron in the nucleus field for multiple values of fractional parameter of the space-dependent fractional Schrödinger equation and for each value of the space-dependent fractional parameter, multiple values of energies are applied. Distances are found at which the probability takes its maximum value. Values of energy obtained in this study corresponding to the maximum value of probability are compared with the energy values resulted from the fractional Bohr’s atom formula in the fractional quantum mechanics.