Fully quantum study of vibrational energy transfer between H2 and D2

Abstract

We present here the results of a detailed study of the collisional transfer of vibrational energy between H₂ and D₂. Following our work on D₂–D₂ collisions [J. Chem. Phys. 59, 6254 (1973)], we carry out a fully quantum treatment of the collision dynamics, assuming a collinear geometry. We have used one fully ab initio and four different model interaction potentials. For both the 10→01 and 11→02 processes, we find that the transition probabilities are extremely sensitive to the choice of potential surface. Another result is that nearest‐atom model potentials yield inelastic probabilities which are too large. We further show that long‐range forces play a far less important role in the case of these off‐resonant processes than for the D₂–D₂ near‐resonant collisions. Also of interest is the result that the calculated V–V transition probabilities are largely insensitive to the choice of a harmonic or Morse oscillator description of the colliding molecules.