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Szabo, P. & Gustafsson, M. (2023). Polyatomic radiative association by quasiclassical trajectory calculations: Formation of HCN and HNC molecules in H + CN collisions. Journal of Chemical Physics, 159(14), Article ID 144112.
Open this publication in new window or tab >>Polyatomic radiative association by quasiclassical trajectory calculations: Formation of HCN and HNC molecules in H + CN collisions
2023 (English)In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 159, no 14, article id 144112Article in journal (Refereed) Published
Abstract [en]

We have developed the polyatomic extension of the established [M. Gustafsson, J. Chem. Phys. 138, 074308 (2013)] classical theory of radiative association in the absence of electronic transitions. The cross section and the emission spectrum of the process is calculated by a quasiclassical trajectory method combined with the classical Larmor formula which can provide the radiated power in collisions. We have also proposed a Monte Carlo scheme for efficient computation of ro-vibrationally quantum state resolved cross sections for radiative association. Besides the method development, the global potential energy and dipole surfaces for H + CN collisions have been calculated and fitted to test our polyatomic semiclassical method.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2023
National Category
Physical Chemistry
Research subject
Applied Physics
Identifiers
urn:nbn:se:ltu:diva-101662 (URN)10.1063/5.0170577 (DOI)
Funder
The Kempe FoundationsKnut and Alice Wallenberg Foundation
Note

Validerad;2023;Nivå 2;2023-10-16 (joosat);

Funder: Belgian Science Policy Office (BELSPO), FED-tWIN REVOCS; European Cooperation in Science and Technology (COST), (No. CA18212 — Molecular Dynamics in the GAS phase (MD-GAS))

Available from: 2023-10-16 Created: 2023-10-16 Last updated: 2023-10-16Bibliographically approved
Fakhardji, W., Szabó, P. & Gustafsson, M. (2021). Direct method for MD simulations of collision-induced absorption: application to an Ar–Xe gas mixture. Journal of Quantitative Spectroscopy and Radiative Transfer, 276, Article ID 107926.
Open this publication in new window or tab >>Direct method for MD simulations of collision-induced absorption: application to an Ar–Xe gas mixture
2021 (English)In: Journal of Quantitative Spectroscopy and Radiative Transfer, ISSN 0022-4073, E-ISSN 1879-1352, Vol. 276, article id 107926Article in journal (Refereed) Published
Abstract [en]

With the reformulation of the classical equations of collision-induced absorption, we present a method to perform the direct computation of the spectral density function. This way the absorption coefficient can be computed from classical molecular dynamics (MD) without the computationally demanding evaluation of the dipole autocorrelation function. In addition, we have developed an algorithm to extract the bound-to-bound dimer contribution to the MD simulated absorption. The method has been tested on the Ar–Xe rare gas system. Comparisons with quantum mechanical (QM) and conventional MD methods validate the approach. The obtained MD bound-to-bound spectra generally agree in shape and magnitude with QM results, including features stemming from rotations and vibrations of the Ar–Xe dimer.

Place, publisher, year, edition, pages
Elsevier, 2021
National Category
Other Physics Topics
Research subject
Applied Physics
Identifiers
urn:nbn:se:ltu:diva-87006 (URN)10.1016/j.jqsrt.2021.107926 (DOI)000701663500011 ()2-s2.0-85114987987 (Scopus ID)
Funder
Luleå University of TechnologyThe Kempe FoundationsKnut and Alice Wallenberg Foundation
Note

Validerad;2021;Nivå 2;2021-09-27 (alebob);

Forskningsfinansiär: COST (European Cooperation in Science and Technology)

Available from: 2021-09-08 Created: 2021-09-08 Last updated: 2021-10-07Bibliographically approved
Szabo, P., Góger, S. & Gustafsson, M. (2021). Formation of the BeH+ and BeD+ Molecules in Be+ + H/D Collisions Through Radiative Association. Frontiers in Astronomy and Space Sciences, 8, Article ID 704953.
Open this publication in new window or tab >>Formation of the BeH+ and BeD+ Molecules in Be+ + H/D Collisions Through Radiative Association
2021 (English)In: Frontiers in Astronomy and Space Sciences, E-ISSN 2296-987X, Vol. 8, article id 704953Article in journal (Refereed) Published
Abstract [en]

Cross sections and rate coefficients for the formation of BeH+ and BeD+ molecules in Be+ + H/D collisions through radiative association are calculated using quantum mechanical perturbation theory and Breit-Wigner theory. The local thermodynamic equilibrium limit of the molecule formation is also studied, since the process is also relevant in environments with high-density and/or strong radiation fields. The obtained rate coefficients may facilitate the kinetic modelling of BeH+/BeD+ production in astrochemical environments as well as the corrosion chemistry of thermonuclear fusion reactors.

Place, publisher, year, edition, pages
Frontiers Media S.A., 2021
Keywords
molecule formation, radiative association, cross secitons, rate consant, quantum dynamic
National Category
Atom and Molecular Physics and Optics Astronomy, Astrophysics and Cosmology Fusion, Plasma and Space Physics
Research subject
Applied Physics
Identifiers
urn:nbn:se:ltu:diva-86497 (URN)10.3389/fspas.2021.704953 (DOI)000690896500001 ()2-s2.0-85117829870 (Scopus ID)
Funder
The Kempe FoundationsKnut and Alice Wallenberg FoundationSwedish National Infrastructure for Computing (SNIC)
Note

Validerad;2021;Nivå 2;2021-08-10 (alebob);

Finansiär: COST (European Cooperation in Science and Technology)

Available from: 2021-07-30 Created: 2021-07-30 Last updated: 2021-12-13Bibliographically approved
Fakhardji, W., Szabo, P., El-Kader, M. & Gustafsson, M. (2020). Molecular dynamics calculations of collision-induced absorption in a gas mixture of neon and krypton. Journal of Chemical Physics, 152(23), Article ID 234302.
Open this publication in new window or tab >>Molecular dynamics calculations of collision-induced absorption in a gas mixture of neon and krypton
2020 (English)In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 152, no 23, article id 234302Article in journal (Refereed) Published
Abstract [en]

We continue the development of the in-house molecular dynamics software package SpaCIAL and test it for the computation of the collision-induced absorption coefficients for a neon (Ne) and krypton (Kr) gas mixture. An apodization procedure for the dipole autocorrelation function is implemented and tested. We also carry out a statistical study of the convergence rate with respect to ensemble size. The resulting absorption coefficients show a good accordance with quantum mechanical results. Comparison with laboratory measurements shows agreement within 10%–20% at T = 295 K. At T = 480 K, a larger difference of 40%–80% is observed, which can presumably be explained by experimental uncertainties. For the study, an empirical (Barker, Fisher, and Watts) interaction-potential [Mol. Phys. 21, 657 (1971)] for Ne–Kr has been developed. Ab initio {coupled cluster with singles and doubles (triples) [CCSD(T)]} potentials for Ne–Ne, Kr–Kr, and Ne–Kr have been computed, as well as the CCSD(T) interaction-induced Ne–Kr dipole moment curve.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2020
National Category
Other Physics Topics
Research subject
Applied Physics
Identifiers
urn:nbn:se:ltu:diva-79571 (URN)10.1063/5.0006186 (DOI)000542649800001 ()32571059 (PubMedID)2-s2.0-85086915263 (Scopus ID)
Funder
Knut and Alice Wallenberg FoundationThe Kempe FoundationsSwedish National Infrastructure for Computing (SNIC)
Note

Validerad;2020;Nivå 2;2020-06-22 (alebob)

Available from: 2020-06-15 Created: 2020-06-15 Last updated: 2021-01-06Bibliographically approved
Fakhardji, W., Szabo, P., El-Kader, M., Haskopoulos, A., Maroulis, G. & Gustafsson, M. (2019). Collision-induced absorption in Ar–Kr gas mixtures: A molecular dynamics study with new potential and dipole data. Journal of Chemical Physics, 151(14), Article ID 144303.
Open this publication in new window or tab >>Collision-induced absorption in Ar–Kr gas mixtures: A molecular dynamics study with new potential and dipole data
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2019 (English)In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 151, no 14, article id 144303Article in journal (Refereed) Published
Abstract [en]

We have implemented a scheme for classical molecular dynamics simulations of collision-induced absorption. The program has been applied to a gas mixture of argon (Ar) and krypton (Kr). The simulations are compared with accurate quantum dynamical calculations. The comparisons of the absorption coefficients show that classical molecular dynamics is correct within 10% for photon wave numbers up to 220 cm−1 at a temperature of 200 K for this system. At higher temperatures, the agreement is even better. Molecular dynamics accounts for many-body interactions, which, for example, give rise to continuous dimer formation and destruction in the gas. In this way, the method has an advantage compared with bimolecular classical (trajectory) treatments. The calculations are carried out with a new empirical Ar–Kr pair potential. This has been obtained through extensive analysis of experimental thermophysical and transport properties. We also present a new high level ab initio Ar–Kr potential curve for comparison, as well as ab initio interaction-induced dipole curves computed with different methods. In addition, the Ar–Kr polarizability and hyperpolarizability are reported. A comparison of the computed absorption spectra with an experiment taken at 300 K shows satisfactory agreement although a difference in absolute magnitude of 10%–15% persists. This discrepancy we attribute mainly to experimental uncertainty.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2019
National Category
Atom and Molecular Physics and Optics Physical Chemistry Other Physics Topics
Research subject
Applied Physics
Identifiers
urn:nbn:se:ltu:diva-76352 (URN)10.1063/1.5099700 (DOI)000500356200026 ()31615255 (PubMedID)2-s2.0-85073264154 (Scopus ID)
Funder
The Kempe FoundationsKnut and Alice Wallenberg Foundation
Note

Validerad;2019;Nivå 2;2019-10-15 (johcin)

Available from: 2019-10-10 Created: 2019-10-10 Last updated: 2021-01-06Bibliographically approved
Szabo, P. & Gustafsson, M. (2019). Formation of the NH molecule and its isotopologues through radiative association. Monthly notices of the Royal Astronomical Society, 483(3), 3574-3578
Open this publication in new window or tab >>Formation of the NH molecule and its isotopologues through radiative association
2019 (English)In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 483, no 3, p. 3574-3578Article in journal (Refereed) Published
Abstract [en]

The rate coefficients and the cross-sections for the formation of imidogen (NH) molecule (and its isotopologues: 15NH and ND) through radiative association are determined by employing quantum mechanical perturbation theory, classical Larmor formula, and Breit–Wigner theory. We suggest the radiative association process as possible route for NH production in diffuse interstellar clouds.

Place, publisher, year, edition, pages
Oxford University Press, 2019
Keywords
molecular processes, scattering, ISM: atoms, ISM: clouds, ISM: molecules
National Category
Atom and Molecular Physics and Optics Composite Science and Engineering Other Physics Topics
Research subject
Applied Physics
Identifiers
urn:nbn:se:ltu:diva-73251 (URN)10.1093/mnras/sty3246 (DOI)000462280000046 ()
Funder
The Kempe FoundationsKnut and Alice Wallenberg Foundation
Note

Validerad;2019;Nivå 2;2019-04-10 (oliekm)

Available from: 2019-03-19 Created: 2019-03-19 Last updated: 2021-03-12Bibliographically approved
Góger, S., Szabo, P., Czakó, G. & Lendvay, G. (2018). Flame Inhibition Chemistry: Rate Coefficients of the Reactions of HBr with CH3 and OH Radicals at High Temperatures Determined by Quasiclassical Trajectory Calculations. Energy & Fuels, 32(10), 10100-10105
Open this publication in new window or tab >>Flame Inhibition Chemistry: Rate Coefficients of the Reactions of HBr with CH3 and OH Radicals at High Temperatures Determined by Quasiclassical Trajectory Calculations
2018 (English)In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 32, no 10, p. 10100-10105Article in journal (Refereed) Published
Abstract [en]

Reactions of HBr with radicals are involved in atmospheric chemistry and in the mechanism of operation of bromine-containing flame retardants. The rate coefficients for two such reactions, HBr + OH and HBr + CH3, are available from earlier experiments at near or below room temperature, relevant for atmospheric chemistry, and in this domain, the activation energy for both has been found to be negative. However, no experimental data are available at combustion temperatures. In this work, to provide reliable data needed for modeling the action of brominated flame suppressants, we used the quasiclassical trajectory (QCT) method in combination with high-level ab initio potential energy surfaces to evaluate the rate coefficients of the two title reactions at combustion temperatures. The QCT calculations have been validated by reproducing the experimental rate coefficients at room temperature. At temperatures between 600 and 3200 K, the QCT rate coefficients display positive activation energies. We recommend the following extended Arrhenius expressions to describe the temperature dependence of the thermal rate coefficients: k6 = (9.86 ± 2.38) × 10–16T(1.23±0.03) exp[(5.93 ± 0.33) kJ mol–1/RT] cm3 molecule–1 s–1 for the HBr + OH → H2O + Br reaction, and k–2 = (4.06 ± 2.72) × 10–18T(1.83±0.08) exp[(7.53 ± 0.18) kJ mol–1/RT] cm3 molecule–1 s–1 for the HBr + CH3 → CH4 + Br reaction. The latter is in very good agreement with the formula proposed by Burgess et al. [Burgess, D. R., Jr.; Babushok, V. I.; Linteris, G. T.; Manion, J. A. A Chemical Kinetic Mechanism for 2-Bromo-3,3,3-trifluoropropene (2-BTP) Flame Inhibition. Int. J. Chem. Kinet. 2015, 47, 533−619, DOI: 10.1002/kin.20923]. The conventional transition state theory has been tested against the rate data obtained by the QCT method and was found to overestimate not only the rate coefficients but also the activation energies

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
National Category
Other Physics Topics
Research subject
Applied Physics
Identifiers
urn:nbn:se:ltu:diva-68839 (URN)10.1021/acs.energyfuels.8b00989 (DOI)000448087000006 ()2-s2.0-85047092946 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-11-19 (johcin) 

Available from: 2018-05-22 Created: 2018-05-22 Last updated: 2019-03-27Bibliographically approved
Fehér, K., Nagy, E., Szabó, P., Juzsakova, T., Srankó, D., Gömöry, Á., . . . Skoda-Földes, R. (2018). Heterogeneous azide–alkyne cycloaddition in the presence of a copper catalyst supported on an ionic liquid polymer/silica hybrid material. Applied organometallic chemistry, 32(6), Article ID e4343.
Open this publication in new window or tab >>Heterogeneous azide–alkyne cycloaddition in the presence of a copper catalyst supported on an ionic liquid polymer/silica hybrid material
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2018 (English)In: Applied organometallic chemistry, ISSN 0268-2605, E-ISSN 1099-0739, Vol. 32, no 6, article id e4343Article in journal (Refereed) Published
Abstract [en]

Heterogeneous copper catalysts were prepared by the deposition of CuI on a hybrid material consisting of silica and a polymer with imidazolium moieties. The solid materials were characterised using solid‐phase NMR, Fourier transform infrared, Raman and X‐ray photoelectron spectroscopies and Brunauer–Emmett–Teller measurements. The formation of copper–carbene complexes was proved from Raman spectra and the results were supported by density functional theory calculations. The catalyst could be recycled efficiently with low loss of copper. Metal leaching was proved to be facilitated by the use of conditions typical for a homogeneous system (the presence of a polar solvent or the addition of a tertiary amine). Besides simple model reactions, the best catalyst was found to be suitable for the synthesis of triazoles of more elaborate structure, such as ferrocene or steroid derivatives.

Place, publisher, year, edition, pages
John Wiley & Sons, 2018
National Category
Other Physics Topics
Research subject
Applied Physics
Identifiers
urn:nbn:se:ltu:diva-68625 (URN)10.1002/aoc.4343 (DOI)000434047600010 ()2-s2.0-85045837688 (Scopus ID)
Available from: 2018-05-04 Created: 2018-05-04 Last updated: 2022-01-21Bibliographically approved
Szabo, P. & Gustafsson, M. (2017). A surface-hopping method for semiclassical calculations of cross sectionsfor radiative association with electronic transitions. Journal of Chemical Physics, 147, Article ID 094308.
Open this publication in new window or tab >>A surface-hopping method for semiclassical calculations of cross sectionsfor radiative association with electronic transitions
2017 (English)In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 147, article id 094308Article in journal (Refereed) Published
Abstract [en]

A semiclassical method based on surface-hopping techniques is developed to model the dynamics of radiative association with electronic transitions. It can be proven that this method is an extension of the established semiclassical formula used in the characterization of diatomic molecule-formation. Our method is tested for diatomic molecules. It gives the same cross sections as the former semiclassical formula but, contrary to the former method, it allows us to follow the fate of the trajectories after the emission of a photon. This means that we can characterize the rovibrational states of the stabilized molecules. Using semiclassical quantization, we can obtain quantum state-resolved cross sections or emission spectra for the radiative association process. The calculated semiclassical state-resolved spectra show general agreement with the result of quantum mechanical perturbation theory. Furthermore, our surface-hopping model is not only applicable for the description of radiative association but it can be used for semiclassical characterization of any molecular process where spontaneous emission occurs

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2017
National Category
Other Physics Topics
Research subject
Applied Physics
Identifiers
urn:nbn:se:ltu:diva-65537 (URN)10.1063/1.5000573 (DOI)000409946200022 ()28886643 (PubMedID)2-s2.0-85029324034 (Scopus ID)
Note

Validerad;2017;Nivå 2;2017-09-08 (andbra)

Available from: 2017-09-08 Created: 2017-09-08 Last updated: 2018-07-10Bibliographically approved
Szabo, P., Zsirka, B., Fertig, D., Horváth, E., Csizmadia, T. & Kristóf, J. (2017). Delaminated kaolinites as potential photocatalysts: Tracking degradation of Na-benzenesulfonate test compound adsorbed on the dry surface of kaolinite nanostructures. Catalysis Today, 287(Supplement C), 37-44
Open this publication in new window or tab >>Delaminated kaolinites as potential photocatalysts: Tracking degradation of Na-benzenesulfonate test compound adsorbed on the dry surface of kaolinite nanostructures
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2017 (English)In: Catalysis Today, ISSN 0920-5861, E-ISSN 1873-4308, Vol. 287, no Supplement C, p. 37-44Article in journal (Refereed) Published
Abstract [en]

Abstract Based on their bandgap values, kaolins can have semiconductive and photocatalytic properties enabling them to use as potential photocatalysts. Kaolinite nanostructures (Knano) and silver-coated kaolinite nanohybrids (Knano(Ag)) were made of ordered (Hinkley Index, HI=1.4) and disordered (HI=0.3) kaolins via intercalation/deintercalation. The book-type kaolin built up from tetrahedral(T)-octahedral(O) double layers has very low photocatalytic activity. At the same time the nanostructures made of individual TO layers show photochemical activity in spite of the fact that their bandgap values are comparable to those of the book-type ones. The presence of Ag on the surface significantly reduced the bandgap and shifted the excitation wavelength towards the visible range. This phenomenon supports the supposition that kaolinite has some semiconductive character. This work presents the connection between photocatalytic activity and morphology for the first time. The surface activity of kaolinite nanostructures and their Ag-hybrids was studied through the decomposition of sodium-benzenesulfonate (BS) test compound with attenuated total reflection Fourier transform infrared spectroscopy (FT-IR/ATR). BS decomposition can be detected on the Knano surface but with low efficiency. The presence of silver can significantly improve the mineralization efficiency. No correlation was found between the activity and the quantity of Ti and Fe contaminants and the amount of Ag on the surface. However, the activity could be correlated with the order-dependent morphology (mixture of semi-hexagonal and nanoscroll-type structures), the pore size and with the increase of the surface coverage.

Place, publisher, year, edition, pages
Elsevier, 2017
Keywords
Kaolinite nanostructures, Ag-nanohybrides, Photocatalysis, Mineralization, FT-IR spectroscopy
National Category
Materials Chemistry Other Physics Topics
Research subject
Applied Physics
Identifiers
urn:nbn:se:ltu:diva-66488 (URN)10.1016/j.cattod.2017.01.051 (DOI)000399006100007 ()2-s2.0-85013059608 (Scopus ID)
Available from: 2017-11-08 Created: 2017-11-08 Last updated: 2021-04-29Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-0271-4846

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