TY - JOUR
T1 - Collisional Quenching of Highly Excited H2 due to H2 Collisions
AU - Wan, Yier
AU - Yang, B. H.
AU - Stancil, P. C.
AU - Balakrishnan, N.
AU - Parekh, Nikhil J.
AU - Forrey, R. C.
N1 - Funding Information:
We thank K. Walker for help with vrrmm. The transition probability for the LAMDA file was adopted by S. Cummings. This research used resources of the Oak Ridge Leadership Computing Facility at the Oak Ridge National Laboratory, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC05-00OR22725. Other computing resources were provided by the Georgia Advanced Computing Resource Center, UNLV National Supercomputing Institute, and the Center for Simula-tional Physics of The University of Georgia. This work was funded by NASA HST Grant HST-AR-13899.
Publisher Copyright:
© 2018. The American Astronomical Society. All rights reserved.
PY - 2018/8/1
Y1 - 2018/8/1
N2 - Rate coefficients for pure rotational quenching in H2(ν 1 = 0, j 1) + H2(ν 2 = 0, j 2) collisions from initial levels of j 1 = 2-31 (j 2 = 0 or 1) to all lower rotational levels are presented. We carried out extensive quantum mechanical close-coupling calculations based on a recently published H2-H2 potential energy surface (PES) developed by Patkowski et al. that has been demonstrated to be more reliable than previous work. Rotational transition cross sections with initial levels of j 1 = 2-14, 18, 19, 24, and 25 were computed for energies ranging from 10-6 to 1000 cm-1, while the coupled-states approximation was adopted from 2000 to 20,000 cm-1. The corresponding rate coefficients were calculated for the temperature range 10-5 ≤ T ≤ 10,000 K. Scaling methods based on the ultra-cold data (10-5-1 K) were used to estimate rate coefficients for all other intermediate rotational states. Comparisons with previous work that adopted different PESs show small discrepancies at high temperatures and in low-energy resonance regions. The astrophysical applications of the current results are briefly discussed, including the rotational H2 critical densities due to para-H2 and ortho-H2 collisions.
AB - Rate coefficients for pure rotational quenching in H2(ν 1 = 0, j 1) + H2(ν 2 = 0, j 2) collisions from initial levels of j 1 = 2-31 (j 2 = 0 or 1) to all lower rotational levels are presented. We carried out extensive quantum mechanical close-coupling calculations based on a recently published H2-H2 potential energy surface (PES) developed by Patkowski et al. that has been demonstrated to be more reliable than previous work. Rotational transition cross sections with initial levels of j 1 = 2-14, 18, 19, 24, and 25 were computed for energies ranging from 10-6 to 1000 cm-1, while the coupled-states approximation was adopted from 2000 to 20,000 cm-1. The corresponding rate coefficients were calculated for the temperature range 10-5 ≤ T ≤ 10,000 K. Scaling methods based on the ultra-cold data (10-5-1 K) were used to estimate rate coefficients for all other intermediate rotational states. Comparisons with previous work that adopted different PESs show small discrepancies at high temperatures and in low-energy resonance regions. The astrophysical applications of the current results are briefly discussed, including the rotational H2 critical densities due to para-H2 and ortho-H2 collisions.
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U2 - 10.3847/1538-4357/aaccf8
DO - 10.3847/1538-4357/aaccf8
M3 - Article
AN - SCOPUS:85051558784
SN - 0004-637X
VL - 862
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 132
ER -