  We apply deep learning for retrieval of the time-dependent bond length in the
dissociating two-dimensional H$_2^{+}$ molecule using photoelectron momentum
distributions. We consider a pump-probe scheme and calculate electron momentum
distributions from strong-field ionization by treating the motion of the nuclei
classically, semiclassically or quantum mechanically. A convolutional neural
network trained on momentum distributions obtained at fixed internuclear
distances retrieves the time-varying bond length with an absolute error of
$0.2$-$0.3$ a.u.
