Title: State-to-state inelastic rotational cross sections in five-atom systems with the multiconfiguration time dependent Hartree method

Abstract

We present a MultiConfiguration Time Dependent Hartree (MCTDH) method as an attractive alternative approach to the usual quantum close-coupling method that approaches some computational limits in the calculation of rotational excitation (and de-excitation) between polyatomic molecules (here collisions between triatomic and diatomic rigid molecules). We have performed a computational investigation of the rotational (de-)excitation of the benchmark rigid rotor H₂O–H₂ system on a recently developed Potential Energy Surface of the complex using the MCTDH method. We focus here on excitations and de-excitations from the 0₀₀, 1₁₁, and 1₁₀ states of H₂O with H₂ in its ground rotational state, looking at all the potential transitions in the energy range 1–200 cm^-1. This work follows a recently completed study on the H₂O–H₂ cluster where we characterized its spectroscopy and more generally serves a broader goal to describe inelastic collision processes of high dimensional systems using the MCTDH method. We find that the cross sections obtained from the MCTDH calculations are in excellent agreement with time independent calculations from previous studies but does become challenging for the lower kinetic energy range of the de-excitation process: that is, below approximately 20 cm^-1 of collision energy, calculations with a relative modest basis become unreliable. Themore » MCTDH method therefore appears to be a useful complement to standard approaches to study inelastic collision for various collision partners, even at low energy, though performing better for rotational excitation than for de-excitation.« less

Authors:

Ndengué, Steve  ^[1];

• Search DOE PAGES for author "Ndengué, Steve"
• Search DOE PAGES for ORCID "0000-0001-7136-3827"

Scribano, Yohann  ^[2];

• Search DOE PAGES for author "Scribano, Yohann"
• Search DOE PAGES for ORCID "0000-0003-3875-5970"

Gatti, Fabien ^[3]; Dawes, Richard  ^[4]

• Search DOE PAGES for author "Dawes, Richard"
• Search DOE PAGES for ORCID "0000-0002-2493-4671"

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+ Show Author Affiliations

1. Univ. of Rwanda, Kigali (Rwanda). ICTP-East African Inst. for Fundamental Research; Missouri Univ. of Science and Technology, Rolla, MO (United States). Dept. of Chemistry
2. Univ. de Montpellier (France). Lab. Univers et Particule de Montpellier
3. Univ. Paris-Sud - Univ. Paris-Saclay, Orsay (France). Inst. de Sciences Moléculaires d’Orsay
4. Missouri Univ. of Science and Technology, Rolla, MO (United States). Dept. of Chemistry

Publication Date:

Tue Oct 01 00:00:00 EDT 2019

Research Org.:

Missouri Univ. of Science and Technology, Rolla, MO (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1803877

Alternate Identifier(s):

OSTI ID: 1567922

Grant/Contract Number:  

SC0019740

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Chemical Physics

Additional Journal Information:

Journal Volume: 151; Journal Issue: 13; Journal ID: ISSN 0021-9606

Publisher:

American Institute of Physics (AIP)

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY