  We investigate the attosecond response of the electronic cloud of a molecular
system to an outer-valence ionization. The time needed for the remaining
electrons to respond to a sudden perturbation in the electronic structure of
the molecule is a measure of the degree of electron correlation. Using the ab
initio multielectron wave-packet propagation method, we show that this response
time can be sensitive to the molecular structure and the symmetry of the
ionized molecular orbital. Our analysis revealed differences in the temporal
signatures of ultrafast charge migration processes in the context of tautomeric
hydrogen in multinuclear systems, and the relevance of distinctive onset of
electron correlation within the overall molecular complexity.
