  It is shown that the Schr\"{o}dinger equation for a system of interacting
particles whose Compton wavelengths are of the same order of magnitude as the
system size is contradictory and is not strictly nonrelativistic, because it is
based on the implicit assumption that the velocity of propagation of
interactions is finite. In the framework of the model of the noncommutative
operators of coordinates and momenta of different particles, the equation for a
wave function which has no above-mentioned drawbacks is deduced. The
significant differences from solutions of the nonrelativistic Schr\"{o}dinger
equation for large values of the interaction constant are found, and the
comparison of analogous results for hydrogenlike atoms with experimental data
is carried out.
