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28 results on '"Jabri, Atef"'

6. Conformational analysis of methoxyphenol isomers using high-resolution spectroscopy and quantum chemistry calculations

Author

Roucou, A, Jabri, Atef, Fontanari, Daniele, Asselin, Pierre, Goubet, M., Dhont, G., Mouret, G., Bocquet, Robin, Hindle, F., Cuisset, A., Institute of Condensed Matterand Nanosciences,Catholic University of Louvain, B-1348 Louvain-la-Neuve, BELGIUM (IMCN), De la Molécule aux Nanos-objets : Réactivité, Interactions et Spectroscopies (MONARIS), Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physico-Chimie de l'Atmosphère (LPCA), Université du Littoral Côte d'Opale (ULCO), Laboratoire de Physique des Lasers, Atomes et Molécules - UMR 8523 (PhLAM), Université de Lille-Centre National de la Recherche Scientifique (CNRS), Physique Moléculaire aux Interfaces (PMI), Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), and Université du Littoral Côte d'Opale (ULCO)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2019

7. Rovibrational laser jet-cooled spectroscopy of the NH3–Ar complex in the ν2 umbrella region of NH3: comparison between new infrared data and an ab initio calculated spectrum*

Author

Asselin, Pierre, Belkhodja, Yacine, Jabri, Atef, Potapov, Alexey, Loreau, Jérôme, Van Der Avoird, Ad, Asselin, Pierre, Belkhodja, Yacine, Jabri, Atef, Potapov, Alexey, Loreau, Jérôme, and Van Der Avoird, Ad

Abstract

Five ortho and para bands of the ν2 umbrella mode of the NH3–Ar van der Waals complex have been recorded at high resolution using jet-cooled infrared laser spectroscopy. A rovibrational analysis provides accurate band centres and upper state rotational constants for the Πs(j = 1,k = 0) ← Σa(j,k = 0) and Σs(j = 1,k = 0) ← Σa(j,k = 0) ortho bands. The puzzling para bands observed in the region of the lower and upper components of the inversion splitting doublet have been assigned by comparison with rovibrational and tunnelling levels and transitions calculated ab initio. The latter calculations are based on the four-dimensional potential energy surface reported by Loreau et al. [J. Chem. Phys. 141, 224303 (2014)], which takes explicitly into account the umbrella motion of the ammonia molecule. The very good agreement found between Πs/a,lower(j = 1,k = 1) ← Σa(j = 1,k = 1) and Πs/a,upper(j = 1,k = 1) ← Σs(j = 1,k = 1) experimental and calculated transitions has been exploited to determine precisely two different inversion splittings in the ν2 state (32.003(1) and 36.008(1) cm−1) from extrapolated Q(0) line frequencies and to obtain a qualitative picture of Coriolis couplings present in both the ν2 = 0 and ν2 = 1 states., SCOPUS: ar.j, DecretOANoAutActif, info:eu-repo/semantics/published

Published
2018

9. Full Conformational Landscape of 3-Methoxyphenol Revealed by Room Temperature mm-wave Rotational Spectroscopy Supported by Quantum Chemical Calculations

Author

UCL - SST/IMCN/NAPS - Nanoscopic Physics, Roucou, Anthony, Fontanari, Daniele, Dhont, Guillaume, Jabri, Atef, Bray, Cédric, Hindle, Francis, Mouret, Gaël, Bocquet, Robin, Cuisset, Arnaud, UCL - SST/IMCN/NAPS - Nanoscopic Physics, Roucou, Anthony, Fontanari, Daniele, Dhont, Guillaume, Jabri, Atef, Bray, Cédric, Hindle, Francis, Mouret, Gaël, Bocquet, Robin, and Cuisset, Arnaud

Abstract

Room temperature millimeter-wave rotational spectroscopy supported by high level of theory calculations have been employed to fully characterise the conformational landscape of 3-Methoxyphenol, a semi-volatile polar oxygenated aromatic compound precursor of secondary organic aerosols in the atmosphere arising from biomass combustion. While previous rotationally-resolved spectroscopic studies in the microwave and in the UV domains failed to observe the complete conformational landscape, the 70–330 GHz rotational spectrum measured in this study reveals the ground state rotational signatures of the four stable conformations theoretically predicted. Moreover, rotational transitions in the lowest energy vibrationally excited states were assigned for two conformers. While the inertial defect of methoxyphenol does not significantly change between conformers and isomers, the excitation of the methoxy out-of-plane bending is the main contribution to the non-planarity of the molecule.

Published
2018

18. MICROWAVE AND FIR SPECTROSCOPY OF DIMETHYLSULFIDE IN THE GROUND, FIRST AND SECOND EXCITED TORSIONAL STATES

Author

Ilyushin, V., primary, Maul, Christof, additional, Bauerecker, Sigurd, additional, Manceron, Laurent, additional, Jabri, Atef, additional, Kwabia Tchana, F., additional, Motiyenko, R., additional, Margulès, L., additional, Alekseev, E., additional, Krapivin, Igor, additional, Pogrebnyak, Mykola, additional, Dorovskaya, Olga, additional, and Armieieva, Iuliia, additional

Published
2017
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20. Rovibrational laser jet-cooled spectroscopy of the NH3-Ar complex in the ν2 umbrella region of NH3: comparison between new infrared data and an ab initio calculated spectrum*.

Author

Asselin, Pierre, Belkhodja, Yacine, Jabri, Atef, Potapov, Alexey, Loreau, Jérôme, and van der Avoird, Ad

Subjects
AMMONIA, POTENTIAL energy surfaces, COUPLING agents (Chemistry), HIGH resolution spectroscopy, INTERMOLECULAR interactions, MICROWAVES
Abstract

Five ortho and para bands of the ν2 umbrella mode of the NH3-Ar van der Waals complex have been recorded at high resolution using jet-cooled infrared laser spectroscopy. A rovibrational analysis provides accurate band centres and upper state rotational constants for the Πs(j = 1,k = 0) ← Σa(j,k = 0) and Σs(j = 1,k = 0) ← Σa(j,k = 0) ortho bands. The puzzling para bands observed in the region of the lower and upper components of the inversion splitting doublet have been assigned by comparison with rovibrational and tunnelling levels and transitions calculated ab initio. The latter calculations are based on the four-dimensional potential energy surface reported by Loreau et al. [J. Chem. Phys. 141, 224303 (2014)], which takes explicitly into account the umbrella motion of the ammonia molecule. The very good agreement found between Πs/a,lower(j = 1,k = 1) ← Σa(j = 1,k = 1) and Πs/a,upper(j = 1,k = 1) ← Σs(j = 1,k = 1) experimental and calculated transitions has been exploited to determine precisely two different inversion splittings in the ν2 state (32.003(1) and 36.008(1) cm−1) from extrapolated Q(0) line frequencies and to obtain a qualitative picture of Coriolis couplings present in both the ν2 = 0 and ν2 = 1 states. [ABSTRACT FROM AUTHOR]

Published
2018
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27. MethylInternal Rotation in the Microwave Spectrumof Vinyl Acetate.

Author

Nguyen, Ha Vinh Lam, Jabri, Atef, Van, Vinh, and Stahl, Wolfgang

Subjects
*MOLECULAR rotation, *VINYL acetate, *MICROWAVE spectroscopy, *MOLECULAR beams, *FOURIER transforms, *PARAMETER estimation, *QUANTUM chemistry
Abstract

The rotational spectrum of vinylacetate, CH3(CO)OCHCH2, was measuredusing two molecular beam Fourier transformmicrowave spectrometers operating in the frequency range from 2 to40 GHz. Large splittings up to 2 GHz occurred due to the internalrotation of the acetyl methyl group CH3CO with a V3potential of 151.492(34)cm–1, much larger than the barrier of approximately100 cm–1often found in acetates. The torsionaltransitions were fitted using three different programs XIAM, ERHAM,and BELGI-Cs, whereby the rotational constants, centrifugal distortionconstants, and the internal rotation parameters could be determinedwith very high accuracy. The experimental results were supported byquantum chemical calculations. For a conformational analysis, potentialenergy surfaces were calculated. [ABSTRACT FROM AUTHOR]

Published
2014
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28. Rovibrational laser jet-cooled spectroscopy of the NH3-Ar complex in the ν2 umbrella region of NH3: comparison between new infrared data and an ab initio calculated spectrum*.

Author

Asselin, Pierre, Belkhodja, Yacine, Jabri, Atef, Potapov, Alexey, Loreau, Jérôme, and van der Avoird, Ad

Subjects
*AMMONIA, *POTENTIAL energy surfaces, *COUPLING agents (Chemistry), *HIGH resolution spectroscopy, *INTERMOLECULAR interactions, *MICROWAVES
Abstract

Five ortho and para bands of the ν2 umbrella mode of the NH3-Ar van der Waals complex have been recorded at high resolution using jet-cooled infrared laser spectroscopy. A rovibrational analysis provides accurate band centres and upper state rotational constants for the Πs(j = 1,k = 0) ← Σa(j,k = 0) and Σs(j = 1,k = 0) ← Σa(j,k = 0) ortho bands. The puzzling para bands observed in the region of the lower and upper components of the inversion splitting doublet have been assigned by comparison with rovibrational and tunnelling levels and transitions calculated ab initio. The latter calculations are based on the four-dimensional potential energy surface reported by Loreau et al. [J. Chem. Phys. 141, 224303 (2014)], which takes explicitly into account the umbrella motion of the ammonia molecule. The very good agreement found between Πs/a,lower(j = 1,k = 1) ← Σa(j = 1,k = 1) and Πs/a,upper(j = 1,k = 1) ← Σs(j = 1,k = 1) experimental and calculated transitions has been exploited to determine precisely two different inversion splittings in the ν2 state (32.003(1) and 36.008(1) cm−1) from extrapolated Q(0) line frequencies and to obtain a qualitative picture of Coriolis couplings present in both the ν2 = 0 and ν2 = 1 states. [ABSTRACT FROM AUTHOR]

Published
2018
Full Text
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