  The dissociation dynamics of the $\tilde{A}$-state of ammonia have been
studied using a resonant multiphoton ionisation probe in a photoelectron
spectroscopy experiment. The use of a resonant intermediate in the multiphoton
ionisation process changes the ionisation propensity, allowing access to
different ion states when compared with equivalent single photon ionisation
experiments. Ionisation through the $E'$ $^1$A$_1'$ Rydberg intermediate means
we maintain overlap with the ion state for an extended period allowing us to
monitor the excited state population for several hundred femtoseconds. The
vibrational states in the photoelectron spectrum show two distinct timescales,
200 fs and 320 fs, that we assign to the non-adiabatic and adiabatic
dissociation processes respectively. The different timescales derive from
differences in the wavepacket trajectories for the two dissociation pathways
that resonantly excite different vibrational states in the intermediate Rydberg
state. The timescales are similar to those obtained from time resolved ion
kinetic energy release measurements, suggesting we can measure the different
trajectories taken out to the region of conical intersection.
