Photoinduced molecular processes start with the interaction of the
instantaneous electric field of the incident light with the electronic degrees
of freedom. This early attosecond electronic motion impacts the fate of the
photoinduced reactions. We report the first observation of attosecond time
scale electron dynamics in a series of small- and medium-sized neutral
molecules (N2, CO2, and C2H4), monitoring time-dependent variations of the
parent molecular ion yield in the ionization by an attosecond pulse, and
thereby probing the time-dependent dipole induced by a moderately strong near-
infrared laser field. This approach can be generalized to other molecular
species and may be regarded as a first example of molecular attosecond Stark
spectroscopy
