1
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Antonelli E, Gougoula E, Walker NR, Schwell M, Nguyen HVL, Kleiner I. A global rho-axis method for fitting asymmetric tops with one methyl internal rotor and two 14N nuclei: Application of BELGI-2N to the microwave spectra of four methylimidazole isomers. J Chem Phys 2024; 160:214309. [PMID: 38836784 DOI: 10.1063/5.0207944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Accepted: 05/08/2024] [Indexed: 06/06/2024] Open
Abstract
A number of internal rotation codes can deal with the combination of one or two internal rotors with one 14N quadrupole nucleus, but once it comes to two 14N nuclei, no such code is available even for the case of one internal rotor. We present here the extension of our internal rotor program called BELGI-2N using the rho-axis method global approach to deal with compounds containing one methyl rotor and two weakly coupling 14N nuclei. To test our new code, we applied it to the microwave data recorded for N-methylimidazole, 2-methylimidazole, 4-methylimidazole, and 5-methylimidazole using a chirped-pulse Fourier transform microwave spectrometer in the 7.0-18.5 GHz frequency range. Compared to the previously published study, BELGI-2N was able to (i) significantly increase the number of assigned and fitted lines, (ii) fit the complete datasets considering both the internal rotation and the 14N nuclear quadrupole coupling effects simultaneously, and (iii) achieve standard deviations within the measurement accuracy for all methylimidazole isomers.
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Affiliation(s)
- Eléonore Antonelli
- Univ Paris Est Creteil and Université Paris Cité, CNRS, LISA, F-94010 Créteil, France
| | - Eva Gougoula
- Chemistry, School of Natural and Environmental Sciences, Newcastle University, Bedson Building, Newcastle Upon Tyne NE1 7RU, United Kingdom
| | - Nicholas R Walker
- Chemistry, School of Natural and Environmental Sciences, Newcastle University, Bedson Building, Newcastle Upon Tyne NE1 7RU, United Kingdom
| | - Martin Schwell
- Univ Paris Est Creteil and Université Paris Cité, CNRS, LISA, F-94010 Créteil, France
| | - Ha Vinh Lam Nguyen
- Univ Paris Est Creteil and Université Paris Cité, CNRS, LISA, F-94010 Créteil, France
- Institut Universitaire de France (IUF), F-75231 Paris, France
| | - Isabelle Kleiner
- Université Paris Cité and Univ Paris Est Creteil, CNRS, LISA, F-75013 Paris, France
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2
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Sun H, Khemissi S, Kleiner I, Nguyen HVL. Low barriers to internal rotation in the microwave spectrum of 2,5-dimethylfluorobenzene. J Chem Phys 2024; 160:094302. [PMID: 38436444 DOI: 10.1063/5.0185005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Accepted: 01/24/2024] [Indexed: 03/05/2024] Open
Abstract
We investigated the rotational spectrum of 2,5-dimethylfluorobenzene containing coupled large amplitude motions of two methyl groups in the frequency range from 2 to 26.5 GHz using a pulsed molecular jet Fourier transform microwave spectrometer. The internal rotation of two inequivalent methyl groups with low torsional barriers (around 16 and 226 cm-1) causes splittings of all rotational transitions into quintets with separations of up to hundreds of MHz between the torsional components. Spectral analysis and modeling of the observed splittings were performed using the programs XIAM and BELGI-Cs-2Tops, whereby the latter achieved measurement accuracy. The methyl internal rotation can be used to examine the electronic and steric environments around the methyl group because they affect the methyl torsional barrier. Electronic properties play a particularly important role in aromatic molecules in the presence of a π-conjugated double bond system. The experimental results were compared with those of quantum chemistry. Benchmark calculations resulted in the conclusion that the B3LYP-D3BJ/6-311++G(d,p) level of theory can be recommended for predicting rotational constants to guide the microwave spectral assignment of dimethylfluorobenzenes in particular and toluene derivatives in general.
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Affiliation(s)
- Haoyue Sun
- Université Paris Cité and Univ Paris Est Creteil, CNRS, LISA, F-75013 Paris, France
| | - Safa Khemissi
- Univ Paris Est Creteil and Université Paris Cité, CNRS, LISA, F-94010 Créteil, France
| | - Isabelle Kleiner
- Université Paris Cité and Univ Paris Est Creteil, CNRS, LISA, F-75013 Paris, France
| | - Ha Vinh Lam Nguyen
- Univ Paris Est Creteil and Université Paris Cité, CNRS, LISA, F-94010 Créteil, France
- Institut Universitaire de France (IUF), F-75231 Paris, France
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3
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Khemissi S, Schwell M, Kleiner I, Nguyen HVL. Approaching the free rotor limit: extremely low methyl torsional barrier observed in the microwave spectrum of 2,4-dimethylfluorobenzene. Phys Chem Chem Phys 2023; 26:402-411. [PMID: 38078469 DOI: 10.1039/d3cp04748b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
The microwave spectrum of 2,4-dimethylfluorobenzene was recorded using a molecular jet Fourier transform microwave spectrometer in the frequency range from 2.0 to 26.5 GHz. The spectral assignment and modeling were challenging due to the large tunnelling splittings resulting from the very low barrier to internal rotation of the p-methyl group that approaches the free rotor limit. Internal rotation splittings arising from two inequivalent o- and p-methyl groups were observed, analysed and modelled using the modified version of the XIAM code and the BELGI-Cs-2Tops code, giving a root-mean-square deviation of 549.1 kHz and 4.5 kHz, respectively, for a data set of 885 rotational lines. The torsional barriers of the o- and p-methyl groups were determined to be 227.039(51) cm-1 and 3.23(40) cm-1, respectively. The V3 barrier observed for the p-methyl group is lower than in any other para-methyl substituted toluene derivatives with coupled internal rotations, becoming the lowest value ever observed to date. The barrier to internal rotation of the o-methyl group next to a fluorine atom is consistently around 220 cm-1, as confirmed by comparing it to barriers observed in other toluene derivatives. The experimental rotational constants were compared to those obtained by quantum chemical calculations.
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Affiliation(s)
- Safa Khemissi
- Univ Paris Est Creteil and Université Paris Cité, CNRS, LISA, F-94010 Créteil, France.
| | - Martin Schwell
- Univ Paris Est Creteil and Université Paris Cité, CNRS, LISA, F-94010 Créteil, France.
| | - Isabelle Kleiner
- Université Paris Cité and Univ Paris Est Creteil, CNRS, LISA, F-75013 Paris, France
| | - Ha Vinh Lam Nguyen
- Univ Paris Est Creteil and Université Paris Cité, CNRS, LISA, F-94010 Créteil, France.
- Institut Universitaire de France (IUF), F-75231 Paris, France
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Baweja S, Antonelli E, Hussain S, Fernández-Ramos A, Kleiner I, Nguyen HVL, Sanz ME. Revealing Internal Rotation and 14N Nuclear Quadrupole Coupling in the Atmospheric Pollutant 4-Methyl-2-nitrophenol: Interplay of Microwave Spectroscopy and Quantum Chemical Calculations. Molecules 2023; 28:molecules28052153. [PMID: 36903397 PMCID: PMC10004196 DOI: 10.3390/molecules28052153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 02/17/2023] [Accepted: 02/17/2023] [Indexed: 03/02/2023] Open
Abstract
The structure and interactions of oxygenated aromatic molecules are of atmospheric interest due to their toxicity and as precursors of aerosols. Here, we present the analysis of 4-methyl-2-nitrophenol (4MNP) using chirped pulse and Fabry-Pérot Fourier transform microwave spectroscopy in combination with quantum chemical calculations. The rotational, centrifugal distortion, and 14N nuclear quadrupole coupling constants of the lowest-energy conformer of 4MNP were determined as well as the barrier to methyl internal rotation. The latter has a value of 106.4456(8) cm-1, significantly larger than those from related molecules with only one hydroxyl or nitro substituent in the same para or meta positions, respectively, as 4MNP. Our results serve as a basis to understand the interactions of 4MNP with atmospheric molecules and the influence of the electronic environment on methyl internal rotation barrier heights.
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Affiliation(s)
- Shefali Baweja
- Department of Chemistry, King’s College London, Britannia House, 7 Trinity Street, London SE1 1DB, UK
| | - Eleonore Antonelli
- Université Paris Est Créteil and Université Paris Cité, CNRS, LISA, F-94010 Créteil, France
| | - Safia Hussain
- Department of Chemistry, King’s College London, Britannia House, 7 Trinity Street, London SE1 1DB, UK
| | - Antonio Fernández-Ramos
- Departamento de Química Física and Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS), Jenaro de la Fuente s/n, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Isabelle Kleiner
- Université Paris Cité and Université Paris Est Créteil, CNRS, LISA, F-75013 Paris, France
| | - Ha Vinh Lam Nguyen
- Université Paris Est Créteil and Université Paris Cité, CNRS, LISA, F-94010 Créteil, France
- Institut Universitaire de France (IUF), 1 rue Descartes, F-75231 Paris, France
- Correspondence: (H.V.L.N.); (M.E.S.)
| | - M. Eugenia Sanz
- Department of Chemistry, King’s College London, Britannia House, 7 Trinity Street, London SE1 1DB, UK
- Correspondence: (H.V.L.N.); (M.E.S.)
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5
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Nguyen HVL, Caminati W, Grabow JU. The LAM of the Rings: Large Amplitude Motions in Aromatic Molecules Studied by Microwave Spectroscopy. Molecules 2022; 27:3948. [PMID: 35745072 PMCID: PMC9230607 DOI: 10.3390/molecules27123948] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 05/27/2022] [Accepted: 06/06/2022] [Indexed: 11/17/2022] Open
Abstract
Large amplitude motions (LAMs) form a fundamental phenomenon that demands the development of specific theoretical and Hamiltonian models. In recent years, along with the strong progress in instrumental techniques on high-resolution microwave spectroscopy and computational capacity in quantum chemistry, studies on LAMs have become very diverse. Larger and more complex molecular systems have been taken under investigation, ranging from series of heteroaromatic molecules from five- and six-membered rings to polycyclic-aromatic-hydrocarbon derivatives. Such systems are ideally suited to create families of molecules in which the positions and the number of LAMs can be varied, while the heteroatoms often provide a sufficient dipole moment to the systems to warrant the observation of their rotational spectra. This review will summarize three types of LAMs: internal rotation, inversion tunneling, and ring puckering, which are frequently observed in aromatic five-membered rings such as furan, thiophene, pyrrole, thiazole, and oxazole derivatives, in aromatic six-membered rings such as benzene, pyridine, and pyrimidine derivatives, and larger combined rings such as naphthalene, indole, and indan derivatives. For each molecular class, we will present the representatives and summarize the recent insights on the molecular structure and internal dynamics and how they help to advance the field of quantum mechanics.
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Affiliation(s)
- Ha Vinh Lam Nguyen
- Univ Paris Est Creteil and Université Paris Cité, CNRS, LISA, F-94010 Créteil, France
- Institut Universitaire de France (IUF), F-75231 Paris, France
| | - Walther Caminati
- Departimento di Chimica ‘G. Ciamican’, Universita degli Studi di Bologna, Via Selmi 2, 40126 Bologna, Italy;
| | - Jens-Uwe Grabow
- Institut für Physikalische Chemie und Elektrochemie, Gottfried-Wilhelm-Leibniz-Universität Hannover, Callinstraße 3A, 30167 Hannover, Germany
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6
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Roucou A, Goubet M, Kleiner I, Bteich S, Cuisset A. Large Amplitude Torsions in Nitrotoluene Isomers Studied by Rotational Spectroscopy and Quantum Chemistry Calculations. Chemphyschem 2020; 21:2523-2538. [PMID: 32857456 DOI: 10.1002/cphc.202000591] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/27/2020] [Indexed: 11/12/2022]
Abstract
Rotational spectra of ortho-nitrotoluene (2-NT) and para-nitrotoluene (4-NT) have been recorded at low and room temperatures using a supersonic jet Fourier Transform microwave (MW) spectrometer and a millimeter-wave frequency multiplier chain, respectively. Supported by quantum chemistry calculations, the spectral analysis of pure rotation lines in the vibrational ground state has allowed to characterise the rotational energy, the hyperfine structure due to the 14 N nucleus and the internal rotation splittings arising from the methyl group. For 2-NT, an anisotropic internal rotation of coupled -CH3 and -NO2 torsional motions was identified by quantum chemistry calculations and discussed from the results of the MW analysis. The study of the internal rotation splittings in the spectra of three NT isomers allowed to characterise the internal rotation potentials of the methyl group and to compare them with other mono-substituted toluene derivatives in order to study the isomeric influence on the internal rotation barrier.
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Affiliation(s)
- Anthony Roucou
- Université du Littoral Côte d'Opale, UR 4493, LPCA, Laboratoire de Physico-Chimie de l'Atmosphère, F-59140, Dunkerque, France.,Institut de la Matière Condensée et des Nanosciences (IMCN), Université catholique de Louvain, Chemin du Cyclotron 2, 1348, Louvain-la-Neuve, Belgium
| | - Manuel Goubet
- Univ. Lille, CNRS, UMR8523 - PhLAM - Physique des Lasers Atomes et Molécules, F-59000, Lille, France
| | - Isabelle Kleiner
- Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), CNRS UMR 7583, Université Paris-Est Créteil & Université de Paris, Institut Pierre Simon Laplace (IPSL), 61 avenue du Général de Gaulle, F-94010, Créteil cedex, France
| | - Sabath Bteich
- Université du Littoral Côte d'Opale, UR 4493, LPCA, Laboratoire de Physico-Chimie de l'Atmosphère, F-59140, Dunkerque, France
| | - Arnaud Cuisset
- Université du Littoral Côte d'Opale, UR 4493, LPCA, Laboratoire de Physico-Chimie de l'Atmosphère, F-59140, Dunkerque, France
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7
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Nguyen HVL, Kleiner I. Understanding (coupled) large amplitude motions: the interplay of microwave spectroscopy, spectral modeling, and quantum chemistry. PHYSICAL SCIENCES REVIEWS 2020. [DOI: 10.1515/psr-2020-0037] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Abstract
A large variety of molecules contain large amplitude motions (LAMs), inter alia internal rotation and inversion tunneling, resulting in tunneling splittings in their rotational spectrum. We will present the modern strategy to study LAMs using a combination of molecular jet Fourier transform microwave spectroscopy, spectral modeling, and quantum chemical calculations to characterize such systems by the analysis of their rotational spectra. This interplay is particularly successful in decoding complex spectra revealing LAMs and providing reference data for fundamental physics, astrochemistry, atmospheric/environmental chemistry and analytics, or fundamental researches in physical chemistry. Addressing experimental key aspects, a brief presentation on the two most popular types of state-of-the-art Fourier transform microwave spectrometer technology, i.e., pulsed supersonic jet expansion–based spectrometers employing narrow-band pulse or broad-band chirp excitation, will be given first. Secondly, the use of quantum chemistry as a supporting tool for rotational spectroscopy will be discussed with emphasis on conformational analysis. Several computer codes for fitting rotational spectra exhibiting fine structure arising from LAMs are discussed with their advantages and drawbacks. Furthermore, a number of examples will provide an overview on the wealth of information that can be drawn from the rotational spectra, leading to new insights into the molecular structure and dynamics. The focus will be on the interpretation of potential barriers and how LAMs can act as sensors within molecules to help us understand the molecular behavior in the laboratory and nature.
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Affiliation(s)
- Ha Vinh Lam Nguyen
- Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), CNRS UMR 7583 , Université Paris-Est Créteil, Université de Paris, Institut Pierre Simon Laplace , 61 avenue du Général de Gaulle, F-94010 , Créteil , France
- Institut Universitaire de France (IUF) , 1 rue Descartes, F-75231 Paris cedex 05, France
| | - Isabelle Kleiner
- Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), CNRS UMR 7583 , Université Paris-Est Créteil, Université de Paris, Institut Pierre Simon Laplace , 61 avenue du Général de Gaulle, F-94010 , Créteil , France
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8
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Klapec DJ, Czarnopys G, Pannuto J. Interpol review of detection and characterization of explosives and explosives residues 2016-2019. Forensic Sci Int Synerg 2020; 2:670-700. [PMID: 33385149 PMCID: PMC7770463 DOI: 10.1016/j.fsisyn.2020.01.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 01/23/2020] [Indexed: 02/06/2023]
Abstract
This review paper covers the forensic-relevant literature for the analysis and detection of explosives and explosives residues from 2016-2019 as a part of the 19th Interpol International Forensic Science Managers Symposium. The review papers are also available at the Interpol website at: https://www.interpol.int/Resources/Documents#Publications.
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Affiliation(s)
- Douglas J. Klapec
- United States Department of Justice, Bureau of Alcohol, Tobacco, Firearms and Explosives, Forensic Science Laboratory, 6000 Ammendale Road, Ammendale, MD, 20705, USA
| | - Greg Czarnopys
- United States Department of Justice, Bureau of Alcohol, Tobacco, Firearms and Explosives, Forensic Science Laboratory, 6000 Ammendale Road, Ammendale, MD, 20705, USA
| | - Julie Pannuto
- United States Department of Justice, Bureau of Alcohol, Tobacco, Firearms and Explosives, Forensic Science Laboratory, 6000 Ammendale Road, Ammendale, MD, 20705, USA
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9
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Nguyen T, Van V, Gutlé C, Stahl W, Schwell M, Kleiner I, Nguyen HVL. The microwave spectrum of 2-methylthiazole: 14N nuclear quadrupole coupling and methyl internal rotation. J Chem Phys 2020; 152:134306. [DOI: 10.1063/1.5142857] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Thuy Nguyen
- Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), CNRS UMR 7583, Université Paris-Est Créteil, Université de Paris, Institut Pierre Simon Laplace, 61 avenue du Général de Gaulle, F-94010 Créteil, France
| | - Vinh Van
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, D-52074 Aachen, Germany
| | - Claudine Gutlé
- Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), CNRS UMR 7583, Université Paris-Est Créteil, Université de Paris, Institut Pierre Simon Laplace, 61 avenue du Général de Gaulle, F-94010 Créteil, France
| | - Wolfgang Stahl
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, D-52074 Aachen, Germany
| | - Martin Schwell
- Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), CNRS UMR 7583, Université Paris-Est Créteil, Université de Paris, Institut Pierre Simon Laplace, 61 avenue du Général de Gaulle, F-94010 Créteil, France
| | - Isabelle Kleiner
- Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), CNRS UMR 7583, Université Paris-Est Créteil, Université de Paris, Institut Pierre Simon Laplace, 61 avenue du Général de Gaulle, F-94010 Créteil, France
| | - Ha Vinh Lam Nguyen
- Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), CNRS UMR 7583, Université Paris-Est Créteil, Université de Paris, Institut Pierre Simon Laplace, 61 avenue du Général de Gaulle, F-94010 Créteil, France
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10
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Nguyen T, Dindic C, Stahl W, Nguyen HVL, Kleiner I. 14N Nuclear quadrupole coupling and methyl internal rotation in the microwave spectrum of 2-methylpyrrole. Mol Phys 2019. [DOI: 10.1080/00268976.2019.1668572] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Thuy Nguyen
- Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), CNRS UMR 7583, Université Paris-Est Créteil, Université de Paris, Institut Pierre Simon Laplace (IPSL), Créteil, France
| | - Christina Dindic
- Institute of Physical Chemistry, RWTH Aachen University, Aachen, Germany
| | - Wolfgang Stahl
- Institute of Physical Chemistry, RWTH Aachen University, Aachen, Germany
| | - Ha Vinh Lam Nguyen
- Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), CNRS UMR 7583, Université Paris-Est Créteil, Université de Paris, Institut Pierre Simon Laplace (IPSL), Créteil, France
| | - Isabelle Kleiner
- Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), CNRS UMR 7583, Université Paris-Est Créteil, Université de Paris, Institut Pierre Simon Laplace (IPSL), Créteil, France
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11
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Jabri A, Fontanari D, Roucou A, Bray C, Hindle F, Dhont G, Mouret G, Bocquet R, Cuisset A. Conformational landscape and inertial defect of methoxyphenol isomers studied by mm-wave spectroscopy and quantum chemistry calculations. J Chem Phys 2019; 150:104303. [PMID: 30876373 DOI: 10.1063/1.5089426] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Because methoxyphenols (MP) are emitted in significant quantities during biomass fires and contribute to the secondary organic aerosols formation which impacts the climate, their gas phase monitoring in the atmosphere is crucial and requires accurate rovibrational cross sections determined with a good knowledge of their ground state (GS) and vibrationally excited state (ES) molecular parameters. Therefore, the rotational spectra of the two isomers, 2-MP (guaïacol) and 4-MP (mequinol), have been measured in absorption and in emission at room temperature using a frequency multiplication chain and a mm-wave Fourier transform chirped-pulse spectrometer, respectively. Guided by quantum chemistry calculations, the conformational landscape has been characterised and the observation of only one rotamer in the spectra of 2-MP and 4-MP has been explained. For 2-MP, the most stable conformation is justified by an intramolecular O-H⋯OCH3 hydrogen-bond which has been characterised by a topology analysis of the electron density. In a global fit including more than 30 000 line assignments, rotational and quartic centrifugal constants of the GS and the three lowest energy ES have been determined allowing to reproduce the millimeter-wave spectra at the experimental accuracy. The same work has been performed on the cis-rotamer of 4-MP highlighting some perturbations marring the fit quality for two vibrationally ES. Finally, the isomeric dependence of the negative inertial defect ΔI agrees with that of the lowest energy out of plane mode ν45, and the variation of ΔI with the degree of vibrational excitation allows a fine estimation of v45 = 1 vibrational wavenumber.
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Affiliation(s)
- A Jabri
- Laboratoire de Physico-Chimie de l'Atmosphère, CNRS EA-4493, Université du Littoral Côte d'Opale, 59140 Dunkerque, France
| | - D Fontanari
- Laboratoire de Physico-Chimie de l'Atmosphère, CNRS EA-4493, Université du Littoral Côte d'Opale, 59140 Dunkerque, France
| | - A Roucou
- Laboratoire de Physico-Chimie de l'Atmosphère, CNRS EA-4493, Université du Littoral Côte d'Opale, 59140 Dunkerque, France
| | - C Bray
- Laboratoire de Physico-Chimie de l'Atmosphère, CNRS EA-4493, Université du Littoral Côte d'Opale, 59140 Dunkerque, France
| | - F Hindle
- Laboratoire de Physico-Chimie de l'Atmosphère, CNRS EA-4493, Université du Littoral Côte d'Opale, 59140 Dunkerque, France
| | - G Dhont
- Laboratoire de Physico-Chimie de l'Atmosphère, CNRS EA-4493, Université du Littoral Côte d'Opale, 59140 Dunkerque, France
| | - G Mouret
- Laboratoire de Physico-Chimie de l'Atmosphère, CNRS EA-4493, Université du Littoral Côte d'Opale, 59140 Dunkerque, France
| | - R Bocquet
- Laboratoire de Physico-Chimie de l'Atmosphère, CNRS EA-4493, Université du Littoral Côte d'Opale, 59140 Dunkerque, France
| | - A Cuisset
- Laboratoire de Physico-Chimie de l'Atmosphère, CNRS EA-4493, Université du Littoral Côte d'Opale, 59140 Dunkerque, France
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12
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Eibl K, Stahl W, Kleiner I, Nguyen HVL. Conformational effect on the almost free internal rotation in 4-hexyn-3-ol studied by microwave spectroscopy and quantum chemistry. J Chem Phys 2018; 149:144306. [DOI: 10.1063/1.5044542] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Konrad Eibl
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, D-52074 Aachen, Germany
- Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), CNRS UMR 7583, Université Paris-Est Créteil, Université Paris Diderot, Institut Pierre Simon Laplace, 61 Avenue du Général de Gaulle, F-94010 Créteil, France
| | - Wolfgang Stahl
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, D-52074 Aachen, Germany
| | - Isabelle Kleiner
- Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), CNRS UMR 7583, Université Paris-Est Créteil, Université Paris Diderot, Institut Pierre Simon Laplace, 61 Avenue du Général de Gaulle, F-94010 Créteil, France
| | - Ha Vinh Lam Nguyen
- Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), CNRS UMR 7583, Université Paris-Est Créteil, Université Paris Diderot, Institut Pierre Simon Laplace, 61 Avenue du Général de Gaulle, F-94010 Créteil, France
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13
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Zhang W, Tang Y, Shi A, Bao L, Shen Y, Shen R, Ye Y. Recent Developments in Spectroscopic Techniques for the Detection of Explosives. MATERIALS (BASEL, SWITZERLAND) 2018; 11:E1364. [PMID: 30082670 PMCID: PMC6120018 DOI: 10.3390/ma11081364] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Revised: 08/01/2018] [Accepted: 08/03/2018] [Indexed: 12/19/2022]
Abstract
Trace detection of explosives has been an ongoing challenge for decades and has become one of several critical problems in defense science; public safety; and global counter-terrorism. As a result, there is a growing interest in employing a wide variety of approaches to detect trace explosive residues. Spectroscopy-based techniques play an irreplaceable role for the detection of energetic substances due to the advantages of rapid, automatic, and non-contact. The present work provides a comprehensive review of the advances made over the past few years in the fields of the applications of terahertz (THz) spectroscopy; laser-induced breakdown spectroscopy (LIBS), Raman spectroscopy; and ion mobility spectrometry (IMS) for trace explosives detection. Furthermore, the advantages and limitations of various spectroscopy-based detection techniques are summarized. Finally, the future development for the detection of explosives is discussed.
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Affiliation(s)
- Wei Zhang
- Department of Applied Chemistry, School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
| | - Yue Tang
- Department of Applied Chemistry, School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
| | - Anran Shi
- Department of Applied Chemistry, School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
| | - Lirong Bao
- Department of Applied Chemistry, School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
| | - Yun Shen
- Department of Applied Chemistry, School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
| | - Ruiqi Shen
- Department of Applied Chemistry, School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
| | - Yinghua Ye
- Department of Applied Chemistry, School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
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