  We study the motion (translational, vibrational, and rotational) of a
diatomic impurity immersed in an electron liquid and exposed to electronic
current. An approach based on the linear response time-dependent density
functional theory combined with the Ehrenfest dynamics leads to a system of
linear algebraic equations, which account for the competing and counteracting
effects of the current-induced force (electron wind) and the electronic
friction. These forces, by means of the dynamic exchange-correlation kernel
$f_{xc}({\bf r},{\bf r}',\omega)$, include the electronic viscosity
contribution. Starting from the ground state at the equilibrium inter-nuclear
distance and applying a current pulse, we observe three phases of the motion:
(I) acceleration due to the prevalence of the current-induced force, (II)
stabilization upon balancing of the two forces, and (III) deceleration due to
the friction after the end of the pulse. The viscous contribution to the force
largely increases the acceleration (deceleration) at the first (third) phase of
the process. For the aluminium HEG electron density, we find this correction to
amount to up to 70% of the total electron wind and friction effects.
