Greetings, I´m taking contact with femtochemistry. As you know, the goal of this area is the real time following of the molecular dinamics, providing the first real experimental data from transition states, resonances, mechanisms of energy redistribution.. and so on. The key to study theese time-resolved dinamics is the preparation of time dependent coherent superposition of quantum states, generating a wave packet and studying it´s evolution. Ultrashort pulses are able to do this. In pump-probe configuration, the pump pulse sets the zero-time of reaction and induces the coherent state, then the probe pulse gets info about it at different time delays. Can anyone talk to me about it? Why are ultrashort pulses capable of doing this? What is the spectroscopic mechanism of probing theese wave packets? Anything you know will be helpful for me. Thanks!