State-to-state photodissociation dynamics of OH radical via the A~2SIGMA~+ state:Fine-structure distributions of the O(~3P_J) product

摘要

Photo-predissociation dynamics of rotational states (N')of OH(A~2SIGMA~+,v'=3 and 4) are studied using high-n Rydberg atom time-of-flight technique.Spin-orbit branchign fractions of O(~3P_J=2,1,0) are measured:-.676+-0.010:0.138:0.186+-0.017 for N'=0 in v'=3 and 0.873+-0.026:0.102+-0.028:0.025+-0.005 for N'=0 in v'=4,in excellent agreement with the recent theory.While OH A~2SIGMA~+ v'=3 predissociates predominantly via a single ~4SIGMA~_-state,v'=4 decays via the ~4SIGMA~_-,~2SIGMA~_-,and ~4II states,and interferences of these dissociation pathways strongly influence the O(~3P_J) fine-structure distributions.D_0(O-H)=35 565+-30 cm~-1 is obtained.