Time Evolution of Unimolecular Processes in Isolated Molecules by Crossed Laser and Molecular Beams.

摘要

The authors have developed a new technique,double absorption photofragment spectroscopy,in which a molecular beam is crossed with an initiation laser pulse followed,after a delay time,by a probe laser pulse and observe the recoiling photodissociation fragments with a mass spectrometer. This technique should allow the observation of the time development of unimolecular processes in isolated molecules over a time span from picoseconds to milliseconds. A first demonstration has been performed,the observation of the time evolution of predissociation in I2B state molecules as a function of their vibrational and rotational state distribution.