Following a single
photon VUV absorption, the N2molecule
dissociates into distinct channels leading to N atoms of different
reactivities. The optically accessible singlets are bound, and dissociation
occurs through spin–orbit induced transfer to the triplets.
There is a forest of coupled electronic states, and we here aim to
trace a path along the nonadiabatic couplings toward a particular
exit channel. To achieve this, we apply a time-reversed quantum dynamical
approach that corresponds to a dissociation running back. It begins
with an atom–atom relative motion in a particular product channel.
Starting with a Gaussian wave packet at the dissociation region of
N2and propagating it backward in time, one can see the
population transferring among the triplets due to a strong nonadiabatic
interaction between these states. Simultaneously, the optically active
singlets get populated because of spin–orbit coupling to the
triplets. Thus, backward propagation traces the nonradiative association
of nitrogen atoms.