TY - JOUR
T1 - Full-dimensional quantum dynamics calculations of H2-H 2 collisions
AU - Balakrishnan, N.
AU - Quéméner, G.
AU - Forrey, R. C.
AU - Hinde, R. J.
AU - Stancil, P. C.
N1 - Funding Information:
This work was supported by NSF Grant Nos. PHY-0855470 (N.B.), ATM-0635715 (N.B.), PHY-0854838 (R.C.F.), and AST-0607733 (P.C.S.). Partial support from National Aeronautics and Space Administration under Grant/Cooperative Agreement No. NNX08AE57A issued by the Nevada NASA EPSCoR program is also acknowledged. We thank F. Otto for providing us their theoretical results and R. Krems for useful discussions and initial collaboration on this project.
PY - 2011/1/7
Y1 - 2011/1/7
N2 - We report quantum dynamics calculations of rotational and vibrational energy transfer in collisions between two para-H2 molecules over collision energies spanning from the ultracold limit to thermal energies. Results obtained using a recent full-dimensional H2 -H2 potential energy surface (PES) developed by Hinde [J. Chem. Phys. 128, 154308 (2008)] are compared with those derived from the Boothroyd, Martin, Keogh, and Peterson (BMKP) PES [J. Chem. Phys. 116, 666 (2002)]. For vibrational relaxation of H2 (v=1,j=0) by collisions with H2 (v=0,j=0) as well as rotational excitations in collisions between ground state H2 molecules, the PES of Hinde is found to yield results in better agreement with available experimental data. A highly efficient near-resonant energy transfer mechanism that conserves internal rotational angular momentum and was identified in our previous study of the H2 -H2 system [Phys. Rev. A 77, 030704(R) (2008)] using the BMKP PES is also found to be reproduced by the Hinde PES, demonstrating that the process is largely insensitive to the details of the PES. In the absence of the near-resonance mechanism, vibrational relaxation is driven by the anisotropy of the potential energy surface. Based on a comparison of results obtained using the Hinde and BMKP PESs with available experimental data, it appears that the Hinde PES provides a more accurate description of rotational and vibrational transitions in H2 -H 2 collisions, at least for vibrational quantum numbers v ≤ 1.
AB - We report quantum dynamics calculations of rotational and vibrational energy transfer in collisions between two para-H2 molecules over collision energies spanning from the ultracold limit to thermal energies. Results obtained using a recent full-dimensional H2 -H2 potential energy surface (PES) developed by Hinde [J. Chem. Phys. 128, 154308 (2008)] are compared with those derived from the Boothroyd, Martin, Keogh, and Peterson (BMKP) PES [J. Chem. Phys. 116, 666 (2002)]. For vibrational relaxation of H2 (v=1,j=0) by collisions with H2 (v=0,j=0) as well as rotational excitations in collisions between ground state H2 molecules, the PES of Hinde is found to yield results in better agreement with available experimental data. A highly efficient near-resonant energy transfer mechanism that conserves internal rotational angular momentum and was identified in our previous study of the H2 -H2 system [Phys. Rev. A 77, 030704(R) (2008)] using the BMKP PES is also found to be reproduced by the Hinde PES, demonstrating that the process is largely insensitive to the details of the PES. In the absence of the near-resonance mechanism, vibrational relaxation is driven by the anisotropy of the potential energy surface. Based on a comparison of results obtained using the Hinde and BMKP PESs with available experimental data, it appears that the Hinde PES provides a more accurate description of rotational and vibrational transitions in H2 -H 2 collisions, at least for vibrational quantum numbers v ≤ 1.
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U2 - 10.1063/1.3511699
DO - 10.1063/1.3511699
M3 - Article
C2 - 21218997
AN - SCOPUS:78651313027
SN - 0021-9606
VL - 134
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
IS - 1
M1 - 014301
ER -