Product branching between reactive and nonreactive pathways in the collisional quenching of OH 4 ~2SIGMA~+radicals by H2

摘要

The collisional quenching of OH radicals in their excited A ~2SIGMA~+electronic state by molecular hydrogen is examined to determine the partitioning between reactive and nonreactive pathways.This is achieved using a pump-probe laser technique to compare the population prepared in the excited OH A ~2SIGMA~+state with that produced in the OH X ~2II ground state from nonreactive quenching.Only a small fraction of the products,less than 15%,arise from nonreactive quenching;reactive quenching is the dominant product channel.The branching between the product channels provides a new dynamical signature of the conical intersection region(s)that couple the excited state potential for OH A ~2SIGMA~++H2 with OH X ~2II+H2 and H2O+H products.