Rovibrational energy transfer in ortho-H2+para-H2 collisions

Abstract

We present the results of a full-dimensional quantum mechanical study of the rovibrational energy transfer in the collision between ortho-H2 and para-H2 in the energy range of 0.1-1.0 eV. The multiconfiguration time-dependent Hartree algorithm has been used to propagate the wave packets on the global potential energy surface by Boothroyd et al. [J. Chem. Phys. 116, 666 (2002)] and on a modification of this surface where the short range anisotropy is reduced. State-to-state attributes such as probabilities or integral cross sections are obtained using the formalism of Tannor and Weeks [J. Chem. Phys. 98, 3884 (1993)] by Fourier transforming the correlation functions. The effect of initial rotation of the diatoms on the inelastic and de-excitation processes is investigated.

Vibration-vibration and vibration-translation energy transfer in H2-H2 collisions: A critical test of experiment with full-dimensional quantum dynamics

“…13,[38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55] Quantum calculations are the primary source of state-resolved rate coefficients for astrophysical modeling. Excitation of rotational and vibrational levels of H 2 by collisions with H, H + , He, H 2 , and electrons followed by emission of quadrupole radiation is considered to be the main cooling mechanism of the primordial gas.…”

“…As a result, many of the early H 2 -H 2 calculations resorted to the rigid-rotor approximation. However, in the last several years, a number of full-dimensional quantum calculations have been reported within the timedependent 45,47,[49][50][51][52] and time-independent 13, 44, 46, 53-55 quantum formalisms. Some of these calculations have adopted the coupled-states approximation, [44][45][46][47] which was shown to be reliable.…”

Erratum: “Rotational excitations in para-H2+para-H2 collisions: Full- and reduced-dimensional quantum wave packet studies comparing different potential energy surfaces” [J. Chem. Phys. 128, 064305 (2008)]

“…3 which were also obtained with our program code, are only very lightly affected by this problem. ͑In the ortho-para case, the initial wave functions for nonzero k 1,2 were mostly set up with positive k 1,2 .…”

Rovibrational energy transfer in collisions of H2with D2: a full-dimensional wave packet propagation study

“…In [28], we have calculated the rotational excitation cross-sections of para-H 2 þ para-H 2 collisions, and in [33], special emphasis has been placed on rovibrational energy transfer in ortho-H 2 þ para-H 2 collisions. Finally, in [34], a systematic comparison of the full-dimensional potential energy surface of Boothroyd-Martin-Keogh-Peterson [35] (BMKP) with the rigid rotor surface of Diep and Johnson (DJ) [36,37] for para-H 2 þ para-H 2 collisions was performed.…”