Quantum scattering calculations of vibration-vibration (VV) and vibration-translation (VT) energy transfer for non-reactive H2-H 2 collisions on a full-dimensional potential energy surface are reported for energies ranging from the ultracold to the thermal regime. The efficiency of VV and VT transfer is known to strongly correlate with the energy gap between the initial and final states. In H2(v=1, j=0) H 2(v=0, j=1) collisions, the inelastic cross section at low energies is dominated by a VV process leading to H2(v=0, j=0) H 2(v=1, j=1) products. At energies above the opening of the v=1, j=2 rotational channel, pure rotational excitation of the para-H2 molecule leading to the formation of H2(v=1, j=2) H2(v=0, j=1) dominates the inelastic cross section. For vibrationally excited H 2 in the v 2 vibrational level colliding with H2(v=0), the efficiency of both VV and VT process is examined. It is found that the VV process leading to the formation of 2H2(v=1) molecules dominates over the VT process leading to H2(v=1) H2(v=0) products, consistent with available experimental data, but in contrast to earlier semiclassical results. Overall, VV processes are found to be more efficient than VT processes, for both distinguishable and indistinguishable H 2-H2 collisions confirming room temperature measurements for v=1 and v 2.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry