QUANTUM-THEORY OF PLANAR 4-ATOM REACTIONS

An exact quantum mechanical theory is developed to treat four-atom rea ctions of the type AB+CD<->(BCD+A, ACD+B), where the atoms are constra ined to move in a plane. The theory makes use of an unbiased set of hy perspherical coordinates. A method is proposed for implementing the th eory that exploits the potential optimized discrete variable represent ation. Application is made to the calculation of rovibrational state-t o-state reaction probabilities for the reaction H-2+OH<->H2O+H, in whi ch the length of the OH spectator bond is held fixed. The results show that a rotating bond approximation, in which the H-2 molecule is not allowed to rotate, gives good results for vibrationally selected react ion probabilities. The effect of reactant rotation and vibration on th e reactivity and product distributions is discussed for the reactions H-2+OH-->H2O+H and H2O+H-->H-2+OH.