Rotational excitation of HDO and D2O by H2: Experimental and theoretical differential cross-sections

Sarma, G.; Yang, Chung-Hsin; Saha, Anubhuti; Parker, David H.; Wiesenfeld, Laurent

doi:10.1063/1.4772600

Cited by 11 publications

(14 citation statements)

References 33 publications

(51 reference statements)

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“…The first-order diffraction channels (1, 0), (−1, 0), (0, 1), (0, −1), (1, 1), and (−1, −1) correspond to a momentum change of one quantum Δ k . We obtained probabilities for scattering of cold n -H 2 (20% j = 0, 75% j = 1, 5% j = 2) 52 scattering from Pt(111) with an initial translational energy parallel to the surface of 0.055 eV.…”

Section: Methodsmentioning

confidence: 99%

Assessment of Two Problems of Specific Reaction Parameter Density Functional Theory: Sticking and Diffraction of H₂ on Pt(111)

2019

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It is important that theory is able to accurately describe dissociative chemisorption reactions on metal surfaces, as such reactions are often rate-controlling in heterogeneously catalyzed processes. Chemically accurate theoretical descriptions have recently been obtained on the basis of the specific reaction parameter (SRP) approach to density functional (DF) theory (DFT), allowing reaction barriers to be obtained with chemical accuracy. However, being semiempirical, this approach suffers from two basic problems. The first is that sticking probabilities (to which SRP density functionals (DFs) are usually fitted) might show differences across experiments, of which the origins are not always clear. The second is that it has proven hard to use experiments on diffractive scattering of H2 from metals for validation purposes, as dynamics calculations using a SRP-DF may yield a rather poor description of the measured data, especially if the potential used contains a van der Waals well. We address the first problem by performing dynamics calculations on three sets of molecular beam experiments on D2 + Pt(111), using four sets of molecular beam parameters to obtain sticking probabilities, and the SRP-DF recently fitted to one set of experiments on D2 + Pt(111). It is possible to reproduce all three sets of experiments with chemical accuracy with the aid of two sets of molecular beam parameters. The theoretical simulations with the four different sets of beam parameters allow one to determine for which range of incidence conditions the experiments should agree well and for which conditions they should show specific differences. This allows one to arrive at conclusions about the quality of the experiments and about problems that might affect the experiments. Our calculations on diffraction of H2 scattering from Pt(111) show both quantitative and qualitative differences with previously measured diffraction probabilities, which were Debye–Waller (DW)-extrapolated to 0 K. We suggest that DW extrapolation, which is appropriate for direct scattering, might fail if the scattering is affected by the presence of a van der Waals well and that theory should attempt to model surface atom motion for reproducing diffraction experiments performed for surface temperatures of 500 K and higher.

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Section: Methodsmentioning

confidence: 99%

Assessment of Two Problems of Specific Reaction Parameter Density Functional Theory: Sticking and Diffraction of H₂ on Pt(111)

2019

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“…16 Compared to atom-molecule systems, the study of moleculemolecule systems is much less mature, and our understanding of bimolecular collisions is rather limited, although significant progress was made recently. 17,18 In bi-molecular collisions, energy transfer between both collision partners can occur, resulting in much more complex collision dynamics compared to atom-molecule collisions. The measurement of rotational energy transfer that occurs in both partners simultaneously, referred to as rotational product-pairs, would yield valuable information on bimolecular scattering processes, and can help us to verify theoretical calculations at an extremely high level.…”

Section: Introductionmentioning

confidence: 99%

Direct observation of product-pair correlations in rotationally inelastic collisions of ND₃ with D₂

Zhi¹,

Loreau

Avoird³

et al. 2019

Phys. Chem. Chem. Phys.

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“…Usually, calculations of inelastic cross sections 12 are carried out using quantum scattering codes such as MOLSCAT. 13 These calculations are not trivial, [14][15][16][17][18][19][20] but recently a significant progress has been achieved in the rotational quenching of H 2 O by H 2 . [21][22][23][24][25] Another outstanding example of such calculations is rotational quenching of methyl formate, HCOOCH 3 (astrophysically relevant small organic molecule, SOM) by He with collision energy E < 30 cm −1 .…”

Section: Introductionmentioning

confidence: 99%

Mixed quantum/classical theory of rotationally and vibrationally inelastic scattering in space-fixed and body-fixed reference frames

Семенов

Babikov

2013

The Journal of Chemical Physics

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We formulated the mixed quantum/classical theory for rotationally and vibrationally inelastic scattering process in the diatomic molecule + atom system. Two versions of theory are presented, first in the space-fixed and second in the body-fixed reference frame. First version is easy to derive and the resultant equations of motion are transparent, but the state-to-state transition matrix is complexvalued and dense. Such calculations may be computationally demanding for heavier molecules and/or higher temperatures, when the number of accessible channels becomes large. In contrast, the second version of theory requires some tedious derivations and the final equations of motion are rather complicated (not particularly intuitive). However, the state-to-state transitions are driven by realvalued sparse matrixes of much smaller size. Thus, this formulation is the method of choice from the computational point of view, while the space-fixed formulation can serve as a test of the bodyfixed equations of motion, and the code. Rigorous numerical tests were carried out for a model system to ensure that all equations, matrixes, and computer codes in both formulations are correct.

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Rotational excitation of HDO and D2O by H2: Experimental and theoretical differential cross-sections

Cited by 11 publications

References 33 publications

Assessment of Two Problems of Specific Reaction Parameter Density Functional Theory: Sticking and Diffraction of H₂ on Pt(111)

Assessment of Two Problems of Specific Reaction Parameter Density Functional Theory: Sticking and Diffraction of H₂ on Pt(111)

Direct observation of product-pair correlations in rotationally inelastic collisions of ND₃ with D₂

Mixed quantum/classical theory of rotationally and vibrationally inelastic scattering in space-fixed and body-fixed reference frames

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Rotational excitation of HDO and D2O by H2: Experimental and theoretical differential cross-sections

Cited by 11 publications

References 33 publications

Assessment of Two Problems of Specific Reaction Parameter Density Functional Theory: Sticking and Diffraction of H2 on Pt(111)

Assessment of Two Problems of Specific Reaction Parameter Density Functional Theory: Sticking and Diffraction of H2 on Pt(111)

Direct observation of product-pair correlations in rotationally inelastic collisions of ND3 with D2

Mixed quantum/classical theory of rotationally and vibrationally inelastic scattering in space-fixed and body-fixed reference frames

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Assessment of Two Problems of Specific Reaction Parameter Density Functional Theory: Sticking and Diffraction of H₂ on Pt(111)

Assessment of Two Problems of Specific Reaction Parameter Density Functional Theory: Sticking and Diffraction of H₂ on Pt(111)

Direct observation of product-pair correlations in rotationally inelastic collisions of ND₃ with D₂