REACTION CROSS-SECTIONS AND RATE CONSTANTS FOR THE F-2(D-2)-]HF(DF)+H(D) REACTIONS FROM QUASI-CLASSICAL TRAJECTORY CALCULATIONS ON A POTENTIAL-ENERGY SURFACE(H)

The dependence of the cross sections for the F+H-2 and F+D-2 reactions on the collision energy has been determined by means of quasiclassica l trajectory calculations (QCT) on the Stark and Werner (SW) ab initio potential energy surface (PES). From these data rate constants as a f unction of temperature have been evaluated. For both reactions, fairly good agreement between the calculated and experimental rate constants is obtained, Our results are compared with previous QCT and quantum m echanical (QM) calculations on other PES, as well as with recent appro ximate QM results on the SW-PES. The rate constants are in close agree ment for the F+D-2 reaction, while for F+H-2 our values are larger tha n the ones obtained on the 6SEC-PES. The more orienting character of t he SW-PES can explain these differences, when the nuclear spin statist ics of H-2 and D-2 are taken into account.