  It is shown that that the exact solution of the Schrodinger equation for the
molecule consisting of two atoms interacting via improved Tietz potential, the
analytical expressions for the energy of the rotational-vibrational levels,
partition function, free energy, mean energy and specific heat, obtained from
the solution in the paper Exact analytical calculations of thermodynamic
functions of gaseous substances", R. Khordad, A. Avazpour, and A. Ghanbari,
Chemical Physics 517 (2019) 30, are incorrect.
