  Sudden ionisation of a relatively large molecule can initiate a
correlation-driven process dubbed charge migration, where the electron density
distribution is expected to rapidly change. Capturing this
few-femtosecond/attosecond charge redistribution represents the real-time
observation of the electron correlation in the molecule. So far, there has been
no experimental evidence of this process. Here we report on a time-resolved
study of the correlation-driven charge migration process occurring in the
bio-relevant molecule adenine after ionisation by a 15-35 eV attosecond pulse .
We find that, the production of intact doubly charged adenine - via a
shortly-delayed laser-induced second ionisation event - represents the
signature of a charge inflation mechanism resulting from the many-body
excitation. This conclusion is supported by first-principles time-dependent
simulations. Our findings opens new important perspectives for the control of
the molecular reactivity at the electronic timescale.
