THE ONE-DIMENSIONAL PHOTOFRAGMENT TRANSLATIONAL SPECTROSCOPIC TECHNIQUE - INTRAMOLECULAR CLOCKING OF ENERGY REDISTRIBUTION FOR MOLECULES FALLING APART

The details of a simple modified form of a one dimensional photofragment translational spectroscopic technique is described which is used to determine the rate of energy distribution in a molecule failing apart. The apparatus utilizes lasers for photodissociation of the parent ion and the ionization of one of the fragments and a one dimensional time of flight mass spectrometer with a pulsed extraction electric field for data collection. This technique uses molecular rotation as an internal clock and the recoil velocity of the fragments as a monitor of the excess energy distribution prior to photodissociation. The method is applied to study the photodissociation dynamics of iodobenzene. The rate of energy distribution in the predissociative pi, pi* state at 304.67 nm is found to be almost-equal-to 23 kcal mol-1 ps-1.