Journal of Chemical Physics, Vol.105, No.23, 10429-10435, 1996
Comparison of Classical and Quantal Calculations for the Reaction O+h-2(Upsilon=0,J)-)Oh(Upsilon’,J’)+h Near-Threshold
State-to-state reaction probabilities have been calculated for the reaction O + H-2(upsilon = 0,J) --> OH(upsilon’,J’)+ H near threshold using the quasiclassical trajectory technique. In most cases the total classical angular momentum J of the system was held equal to zero. The procedure for "quantizing" the product vibrational energy is somewhat ambiguous, and two procedures were used. The results were compared with the quantal calculations of Chatfield et al. on the same system for J = 0. Both the classical and quantal calculations give very state-specific product distributions. The agreement between the classical and quantal calculations is reasonably good, particularly for the classical procedure which conserves the total product internal energy during the quantization procedure. The agreement is worst for J = 0. For the case J = 14 we have also carried out a calculation for all J values (i.e., all impact parameters and initial orientations) of the product density distribution P(E(vib)’ E(rot)’) and compared it with the comparable distribution for J = 0. Here, E(vib)’ and E(rot)’, are the product vibrational and rotational energies. The results for all J show a peaked product distribution, but it is broader than that for J = 0 and it has a somewhat different correlation between E(vib)’ and E(rot)’.
Keywords:POTENTIAL-ENERGY SURFACES;PRODUCT PROBABILITY-DISTRIBUTIONS;TRAJECTORY CALCULATIONS;VIBRATIONAL ENERGY;REACTION DYNAMICS;FOURIER-SERIES;+ H-2;O(P-3)+H2;EXPANSION;STATES