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Publications (10 of 65) Show all publications
Gustafsson, M., Leigh, F. & Orton, G. (2019). A computational study of hydrogen dimers in giant-planet infrared spectra. In: International Conference on Spectral Lines Shapes : 17–22 June 2018, Dublin City University, Ireland: . Paper presented at 24th International Conference on Spectral Lines Shapes (ICSLS 2018). , 1289, Article ID 012010.
Open this publication in new window or tab >>A computational study of hydrogen dimers in giant-planet infrared spectra
2019 (English)In: International Conference on Spectral Lines Shapes : 17–22 June 2018, Dublin City University, Ireland, 2019, Vol. 1289, article id 012010Conference paper, Published paper (Refereed)
Series
J. Phys : Conf. Ser.
National Category
Astronomy, Astrophysics and Cosmology Atom and Molecular Physics and Optics Other Physics Topics
Research subject
Applied Physics
Identifiers
urn:nbn:se:ltu:diva-76702 (URN)10.1088/1742-6596/1289/1/012010 (DOI)
Conference
24th International Conference on Spectral Lines Shapes (ICSLS 2018)
Available from: 2019-11-14 Created: 2019-11-14 Last updated: 2019-11-14
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)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: 2019-10-25Bibliographically approved
Fakhardji, W., El-Kader, M., Haskopoulos, A., Maroulis, G. & Gustafsson, M. (2019). Contribution from dimers to the collision-induced absorption spectra in an Ar–Kr gas mixture. In: John Costello (Ed.), International Conference on Spectral Lines Shapes: 17–22 June 2018, Dublin City University, Ireland. Paper presented at 24th International Conference on Spectral Line Shapes (ICSLS 2018). , 1289, Article ID 012021.
Open this publication in new window or tab >>Contribution from dimers to the collision-induced absorption spectra in an Ar–Kr gas mixture
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2019 (English)In: International Conference on Spectral Lines Shapes: 17–22 June 2018, Dublin City University, Ireland / [ed] John Costello, 2019, Vol. 1289, article id 012021Conference paper, Published paper (Refereed)
Series
J. Phys.: Conf. Ser.
National Category
Astronomy, Astrophysics and Cosmology Atom and Molecular Physics and Optics
Research subject
Applied Physics
Identifiers
urn:nbn:se:ltu:diva-76697 (URN)10.1088/1742-6596/1289/1/012021 (DOI)
Conference
24th International Conference on Spectral Line Shapes (ICSLS 2018)
Available from: 2019-11-13 Created: 2019-11-13 Last updated: 2019-11-13
Öström, J., Bezrukov, D. S., Nyman, G. & Gustafsson, M. (2019). Erratum: “Reaction rate constant for radiative association of CF+” [J. Chem. Phys. 144, 044302 (2016)] (ed.). Journal of Chemical Physics, 150(24), Article ID 249901.
Open this publication in new window or tab >>Erratum: “Reaction rate constant for radiative association of CF+” [J. Chem. Phys. 144, 044302 (2016)]
2019 (English)In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 150, no 24, article id 249901Article in journal (Refereed) Published
Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2019
National Category
Other Physics Topics
Research subject
Applied Physics
Identifiers
urn:nbn:se:ltu:diva-75549 (URN)10.1063/1.5109231 (DOI)000473303200045 ()
Note

Erratum in: Journal of Chemical Physics, vol.144, nr. 4, 044302, DOI:10.1063/1.4940216 

Available from: 2019-08-16 Created: 2019-08-16 Last updated: 2019-08-16Bibliographically approved
Zámečníková, M., Soldán, P., Gustafsson, M. & Nyman, G. (2019). Formation of CO+ by radiative association. Monthly notices of the Royal Astronomical Society, 489(2), 2954-2960
Open this publication in new window or tab >>Formation of CO+ by radiative association
2019 (English)In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 489, no 2, p. 2954-2960Article in journal (Refereed) Published
Abstract [en]

We theoretically estimate formation rate coefficients for CO+ through the radiative association of C+(2P) with O(3P). In 1989, Petuchowski et al. claimed radiative association to be the most important route for CO+ formation in SN 1987A. In 1990, Dalgarno, Du and You challenged this claim. Therefore, in this study, we improve previous estimates of the radiative association rate coefficients for forming CO+ from C+(2P) and O(3P). To do this, we perform quantum mechanically based perturbation theory calculations as well as semiclassical calculations, which are combined with Breit–Wigner theory in order to add the effect of shape resonances. We explicitly include four electronic transitions. The required potential energy and transition dipole-moment curves are obtained through large basis set multireference configuration interaction electronic structure calculations. We report cross-sections and from these we obtain rate coefficients in the range of 10 –10 000 K, finding that the CO+ formation rate coefficient is larger than the previous estimate by Dalgarno et al. Still our results support their claim that in SN 1987A, CO is mainly formed through radiative association and not through the charge transfer reaction CO+ + O → CO + Oas earlier suggested by Petuchowski et al.

Place, publisher, year, edition, pages
Oxford University Press, 2019
National Category
Astronomy, Astrophysics and Cosmology
Research subject
Applied Physics
Identifiers
urn:nbn:se:ltu:diva-76048 (URN)10.1093/mnras/stz2354 (DOI)000489298100109 ()2-s2.0-85075180066 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-09-23 (johcin)

Available from: 2019-09-18 Created: 2019-09-18 Last updated: 2019-11-25Bibliographically 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 Journals, 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: 2019-04-10Bibliographically approved
Gustafsson, M. & Forrey, R. C. (2019). Semiclassical methods for calculating radiative association rate constants for different thermodynamic conditions: Application to formation of CO, CN, and SiN. Journal of Chemical Physics, 150(22), Article ID 224301.
Open this publication in new window or tab >>Semiclassical methods for calculating radiative association rate constants for different thermodynamic conditions: Application to formation of CO, CN, and SiN
2019 (English)In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, ISSN 0021-9606, Vol. 150, no 22, article id 224301Article in journal (Refereed) Published
Abstract [en]

It is well-known that resonances can serve as a catalyst for molecule formation. Rate constants for resonance-induced molecule formation are phenomenological as they depend upon the mechanism used to populate the resonances. Standard treatments assume tunneling from the continuum is the only available population mechanism, which means long-lived quasibound states are essentially unpopulated. However, if a fast resonance population mechanism exists, the long-lived quasibound states may be populated and give rise to a substantial increase in the molecule formation rate constant. In the present work, we show that the semiclassical formula of Kramers and ter Haar [Bull. Astron. Inst. Neth. 10, 137 (1946)] may be used to compute rate constants for radiative association in the limit of local thermodynamic equilibrium. Comparisons are made with quantum mechanical and standard semiclassical treatments, and results are shown for two limits which provide upper and lower bounds for the six most important radiative association reactions leading to the formation of CO, CN, and SiN. These results may have implications for interstellar chemistry in molecular clouds, where the environmental and thermodynamic conditions often are uncertain.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2019
National Category
Atom and Molecular Physics and Optics Other Physics Topics
Research subject
Applied Physics
Identifiers
urn:nbn:se:ltu:diva-74401 (URN)10.1063/1.5090587 (DOI)000471692400009 ()31202215 (PubMedID)2-s2.0-85067230821 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-06-17 (svasva)

Available from: 2019-06-11 Created: 2019-06-11 Last updated: 2019-07-10Bibliographically approved
Karman, T., Gordon, I., van der Avoird, A., Baranov, Y., Boulet, C., Drouin, B., . . . van der Zande, W. (2019). Update of the HITRAN collision-induced absorption section. Icarus (New York, N.Y. 1962), 328, 160-175
Open this publication in new window or tab >>Update of the HITRAN collision-induced absorption section
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2019 (English)In: Icarus (New York, N.Y. 1962), ISSN 0019-1035, E-ISSN 1090-2643, Vol. 328, p. 160-175Article in journal (Refereed) Published
Abstract [en]

Correct parameterization of the Collision-induced Absorption (CIA) phenomena is essential for accurate modeling of planetary atmospheres. The HITRAN spectroscopic database provides these parameters in a dedicated section. Here, we significantly revise and extend the HITRAN CIA data with respect to the original effort described in Richard et al. [JQSRT 113, 1276 (2012)]. The extension concerns new collisional pairs as well as wider spectral and temperature ranges for the existing pairs. The database now contains CIA for N2N2, N2H2, N2-CH4, N2H2O, N2O2, O2O2, O2-CO2, CO2-CO2, H2H2, H2He, H2-CH4, H2H, HHe, CH4-CH4, CH4-CO2, CH4He, and CH4Ar collision pairs. The sources of data as well as their validation and selection are discussed. A wish list to eliminate remaining deficiencies or lack of data from the astrophysics perspective is also presented.

Place, publisher, year, edition, pages
Elsevier, 2019
National Category
Atom and Molecular Physics and Optics Other Physics Topics
Research subject
Applied Physics
Identifiers
urn:nbn:se:ltu:diva-73252 (URN)10.1016/j.icarus.2019.02.034 (DOI)000469159500014 ()2-s2.0-85063527773 (Scopus ID)
Funder
Knut and Alice Wallenberg Foundation
Note

Validerad;2019;Nivå 2;2019-04-08 (svasva)

Available from: 2019-03-19 Created: 2019-03-19 Last updated: 2019-06-19Bibliographically approved
El-Kader, M., Godet, J.-L., Gustafsson, M. & Maroulis, G. (2018). Multi-property isotropic intermolecular potentials and predicted spectral lineshapes of collision-induced absorption (CIA), collision-induced light scattering (CILS) and collision-induced hyper-Rayleigh scattering (CIHR) for H2Ne, −Kr and −Xe. Journal of Quantitative Spectroscopy and Radiative Transfer, 209, 232-242
Open this publication in new window or tab >>Multi-property isotropic intermolecular potentials and predicted spectral lineshapes of collision-induced absorption (CIA), collision-induced light scattering (CILS) and collision-induced hyper-Rayleigh scattering (CIHR) for H2Ne, −Kr and −Xe
2018 (English)In: Journal of Quantitative Spectroscopy and Radiative Transfer, ISSN 0022-4073, E-ISSN 1879-1352, Vol. 209, p. 232-242Article in journal (Refereed) Published
Abstract [en]

Quantum mechanical lineshapes of collision-induced absorption (CIA), collision-induced light scattering (CILS) and collision-induced hyper-Rayleigh scattering (CIHR) at room temperature (295 K) are computed for gaseous mixtures of molecular hydrogen with neon, krypton and xenon. The induced spectra are detected using theoretical values for induced dipole moment, pair-polarizability trace and anisotropy, hyper-polarizability and updated intermolecular potentials. Good agreement is observed for all spectra when the literature and the present potentials which are constructed from the transport and thermo-physical properties are used.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Other Physics Topics
Research subject
Applied Physics
Identifiers
urn:nbn:se:ltu:diva-67823 (URN)10.1016/j.jqsrt.2018.01.035 (DOI)000428834000020 ()2-s2.0-85056241181 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-03-02 (andbra)

Available from: 2018-03-02 Created: 2018-03-02 Last updated: 2018-12-03Bibliographically approved
Hartmann, J.-M., Tran, H., Armante, R., Boulet, C., Campargue, A., Forget, F., . . . Toon, G. C. (2018). Recent advances in collisional effects on spectra of molecular gases and their practical consequences. Journal of Quantitative Spectroscopy and Radiative Transfer, 213, 178-227
Open this publication in new window or tab >>Recent advances in collisional effects on spectra of molecular gases and their practical consequences
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2018 (English)In: Journal of Quantitative Spectroscopy and Radiative Transfer, ISSN 0022-4073, E-ISSN 1879-1352, Vol. 213, p. 178-227Article in journal (Refereed) Published
Abstract [en]

We review progress, since publication of the book "Collisional effects on molecular spectra: Laboratory experiments and models, consequences for applications" (Elsevier, Amsterdam, 2008), on measuring, modeling and predicting the influence of pressure (ie of intermolecular collisions) on the spectra of gas molecules. We first introduce recently developed experimental techniques of high accuracy and sensitivity. We then complement the above mentioned book by presenting the theoretical approaches, results and data proposed (mostly) in the last decade on the topics of isolated line shapes, line-broadening and -shifting, line-mixing, the far wings and associated continua, and collision-induced absorption. Examples of recently demonstrated consequences of the progress in the description of spectral shapes for some practical applications (metrology, probing of gas media, climate predictions) are then given. Remaining issues and directions for future research are finally discussed.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Other Physics Topics
Research subject
Applied Physics
Identifiers
urn:nbn:se:ltu:diva-68058 (URN)10.1016/j.jqsrt.2018.03.016 (DOI)000434001400019 ()
Note

Validerad;2018;Nivå 2;2018-05-17 (andbra)

Available from: 2018-03-26 Created: 2018-03-26 Last updated: 2018-06-21Bibliographically approved
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Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-7629-0169

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