  In the first order of perturbation theory, the total energy of a diatomic
molecule in the ground state is calculated taking into account the Pauli
principle and plasma oscillations of atomic electrons. The Fourier component of
the potential energy of interaction of an atom with an atom has the form of a
polynomial of the fourth degree of the atomic form factor. Numerical
calculation is performed for the atomic form factor in the approximation of
hydrogen-like wave functions, which approximate the solution of the
Hartree-Fock equation for an isolated atom. It is shown that taking into
account the plasma oscillations of atomic electrons leads to a self-consistent
system of equations, the numerical solution of which makes it possible to
determine the elastic constant, that is, the value of the second derivative at
the minimum of the potential energy of the molecule. The total energy for
nitrogen and fluorine molecules is calculated.
