Association, Dissociation, and the Acceleration and Suppression of Reactions by Laser Pulses

Relating transition-state spectroscopy to standard chemical spectroscopic processes

“…Starting with the initial spectral analysis of Volker, Metiu, Almeida, Marcus, and Zewail [14], the conceptual basis of femtochemistry has been seeded in the time-dependent understanding of spectroscopy pioneered by Heller [15][16][17]. Typically wavepackets corresponding to experimentally generated initial conditions [18] are followed and analysed, with, e.g., works by Tannor [19][20][21][22][23][24][25] and by Shapiro [26][27][28][29][30][31][32] showing how chemical control can be achieved, exploiting the non-ergodic nature of femtochemistry [14,16,[33][34][35]. In general, the existence and possible role of quantum coherence in this non-ergodic motion remains a critical question [36][37][38]; quantum coherence requires much more than just ordered classical motion as the phase difference between quantum wavepackets propagating through equilibrium systems in thermal environments must also be maintained, generating quantum entanglement [39].…”