A simple method for measurement of the full three-dimensional velocity distribution of photofragments and reaction products

We describe and demonstrate a simple and general laser spectroscopic approach for quantum-state-resolved measurement of all three components of the recoil velocity of the products of photodissociation or photoinduced chemical reactions. The method relies on pulsed-laser determination of the time-of-flight distribution of the products. We call this method POSTS, for position sensitive translational spectroscopy. POSTS requires only a single probe laser, which does not have to have a narrow frequency bandwidth. The method is applicable to all atomic and molecular species and will work with most laser detection schemes.