Photodissociation dynamics of H2O at 121.6 nm: Effect of parent rotational excitation on reaction pathways

Photodissociation dynamics of H2O at 121.6 nm through the B 1A1′ state have been studied using the high-resolution H atom Rydberg tagging technique. Experimental evidences show two different dissociation pathways to form the ground OH (X,v=0) products: dissociation through the B–X conical intersection, and dissociation through B–A Coriolis coupling. By preparing the H2O molecules at higher rotational temperatures, dissociation through the B–A Coriolis coupling pathway can be enhanced.