  In a recent paper Castellanos-Jaramillo and Castellanos-Moreno proposed a
simple quantum-mechanical model for an electron in the vicinity of an ionized
nanostructure with a permanent electric dipole. They chose the interaction of
the electron with the charge and the dipole in such a way that the resulting
Schr\"{o}dinger equation is separable into radial and angular parts. In this
comment we show that those authors did not solve the angular eigenvalue
equation with proper periodic boundary conditions and that they also made a
mistake in the elimination of the first derivative in the radial equation. Such
errors invalidate their results of the Einstein coefficients for the $\left(
GaAs\right)_{3}$ system considered.
