Metal–metal and metal–hydrogen reactive transition states

Atomic line broadening has traditionally emphasized resonance broadening by like atoms and ‘inert perturber’ broadening by rare gases and hydrogen. Such methods are ideal for qualitative and quantitative understanding of reactive transition states, including especially non-adiabatic interactions and polarization, orientation and alignment effects. Experiments at Iowa include a variety of such studies with alkali-metal and alkaline-earth metal atoms, e.g. diatomic photodissociation (including state-selected photodissociation through quasibound resonances) and reactive transition-state absorption. In each case theoretical information is available concerning the relevant potential-energy curves (or surfaces) and their couplings, and there are approximate dynamical theories (e.g. orbital locking) to be tested. A summary of recent experimental results and theoretical comparisons emphasizing diatomic photodissociation and its relation to transition state absorption will be presented.