The results are shown in Fig. , which displays the SE, ESA, and hot GSB spectra corresponding to the trans (upper panels) and cis (lower panels) isomers. The trajectories leading to the trans- The methodology has been tested and illustrated by the ab initio evaluation of TA PP spectra of realistic molecular systems, azobenzene and the PSB4. For both molecules, the SE and ESA spectra were demonstrated to give a direct fingerprint of the excited state wavepacket dynamics and permit the monitoring of the isomerization pathways en route to the final photoproducts.