1
|
Petrova TM, Solodov AM, Solodov AA, Deichuli VM, Starikov VI. Measurements and calculations of H2-broadening and shifting parameters of water vapour transitions in a wide spectral region. Mol Phys 2018. [DOI: 10.1080/00268976.2018.1503743] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Tatiana M. Petrova
- Department of Spectroscopy, V.E. Zuev Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences, Tomsk, Russia
| | - Alexander M. Solodov
- Department of Spectroscopy, V.E. Zuev Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences, Tomsk, Russia
| | - Alexander A. Solodov
- Department of Spectroscopy, V.E. Zuev Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences, Tomsk, Russia
| | - Vladimir M. Deichuli
- Department of Spectroscopy, V.E. Zuev Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences, Tomsk, Russia
- Department of Photonics and Informatics, National Research Tomsk State University, Tomsk, Russia
| | - Vitalii I. Starikov
- Department of Advanced Mathematics, Tomsk State University of Control System and Radio Electronics, Tomsk, Russia
- Department of Informational Systems, National Research Tomsk Polytechnic University, Tomsk, Russia
| |
Collapse
|
2
|
Jellali C, Galalou S, Cuisset A, Dhib M, Aroui H. Semi-classical calculations of self-broadening coefficients of OCS and HCN at temperatures between 200 K and 298 K. JOURNAL OF MOLECULAR SPECTROSCOPY 2016; 329:35-42. [PMID: 27812224 PMCID: PMC5084834 DOI: 10.1016/j.jms.2016.08.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 08/19/2016] [Accepted: 08/22/2016] [Indexed: 06/06/2023]
Abstract
For some temperatures of atmospheric interest from 200 to 298 K, the self-broadening coefficients of OCS-OCS and HCN-HCN collisional systems, at different strengths of electrostatic interactions, were calculated respectively for ν1 and ν2 bands for a wide range of rotational quantum numbers J. In particular, we have considered some lines that were not studied previously. We have employed the approximation of bi-resonance functions (Starikov, 2012) in the frame of the semiclassical model of Robert and Bonamy with exact trajectory (RBE). The calculated results are found to be fully consistent with the available experimental values of self-broadening coefficients of OCS and HCN. A comparative study shows that the RBE calculations reproduce the dependence of broadening coefficients on quantum number J much better than the simpler Robert and Bonamy model with parabolic trajectory (RB) for all considered temperatures.
Collapse
Affiliation(s)
- C. Jellali
- Laboratoire de Dynamique Moléculaire et Matériaux Photoniques, Université de Tunis, Ecole Nationale Supérieure d’Ingénieurs de Tunis, 5 Av. Taha Hussein, Tunis, Tunisia
| | - S. Galalou
- Laboratoire de Dynamique Moléculaire et Matériaux Photoniques, Université de Tunis, Ecole Nationale Supérieure d’Ingénieurs de Tunis, 5 Av. Taha Hussein, Tunis, Tunisia
| | - A. Cuisset
- Laboratoire de Physico-Chimie de l’Atmosphère EA 4493, Univ. Littoral Côte d’Opale, 59140 Dunkerque, France
- Université de Lille, F-59000 Lille, France
| | - M. Dhib
- Laboratoire de Dynamique Moléculaire et Matériaux Photoniques, Université de Tunis, Ecole Nationale Supérieure d’Ingénieurs de Tunis, 5 Av. Taha Hussein, Tunis, Tunisia
| | - H. Aroui
- Laboratoire de Dynamique Moléculaire et Matériaux Photoniques, Université de Tunis, Ecole Nationale Supérieure d’Ingénieurs de Tunis, 5 Av. Taha Hussein, Tunis, Tunisia
| |
Collapse
|
3
|
Ma Q, Boulet C, Tipping RH. Effects on calculated half-widths and shifts from the line coupling for asymmetric-top molecules. J Chem Phys 2014; 140:244301. [PMID: 24985632 DOI: 10.1063/1.4883058] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The refinement of the Robert-Bonamy formalism by considering the line coupling for linear molecules developed in our previous studies [Q. Ma, C. Boulet, and R. H. Tipping, J. Chem. Phys. 139, 034305 (2013); 140, 104304 (2014)] have been extended to asymmetric-top molecules. For H2O immersed in N2 bath, the line coupling selection rules applicable for the pure rotational band to determine whether two specified lines are coupled or not are established. Meanwhile, because the coupling strengths are determined by relative importance of off-diagonal matrix elements versus diagonal elements of the operator -iS1 - S2, quantitative tools are developed with which one is able to remove weakly coupled lines from consideration. By applying these tools, we have found that within reasonable tolerances, most of the H2O lines in the pure rotational band are not coupled. This reflects the fact that differences of energy levels of the H2O states are pretty large. But, there are several dozen strongly coupled lines and they can be categorized into different groups such that the line couplings occur only within the same groups. In practice, to identify those strongly coupled lines and to confine them into sub-linespaces are crucial steps in considering the line coupling. We have calculated half-widths and shifts for some groups, including the line coupling. Based on these calculations, one can conclude that for most of the H2O lines, it is unnecessary to consider the line coupling. However, for several dozens of lines, effects on the calculated half-widths from the line coupling are small, but remain noticeable and reductions of calculated half-widths due to including the line coupling could reach to 5%. Meanwhile, effects on the calculated shifts are very significant and variations of calculated shifts could be as large as 25%.
Collapse
Affiliation(s)
- Q Ma
- NASA/Goddard Institute for Space Studies and Department of Applied Physics and Applied, Mathematics, Columbia University, 2880 Broadway, New York, New York 10025, USA
| | - C Boulet
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS (UMR8214) et Université Paris-Sud Bât 350, Campus d'Orsay F-91405, France
| | - R H Tipping
- Department of Physics and Astronomy, University of Alabama, Tuscaloosa, Alabama 35487-0324, USA
| |
Collapse
|
4
|
Ma Q, Boulet C, Tipping RH. Two dimensional symmetric correlation functions of the Ŝ operator and two dimensional Fourier transforms: considering the line coupling for P and R lines of linear molecules. J Chem Phys 2014; 140:104304. [PMID: 24628166 DOI: 10.1063/1.4867417] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The refinement of the Robert-Bonamy (RB) formalism by considering the line coupling for isotropic Raman Q lines of linear molecules developed in our previous study [Q. Ma, C. Boulet, and R. H. Tipping, J. Chem. Phys. 139, 034305 (2013)] has been extended to infrared P and R lines. In these calculations, the main task is to derive diagonal and off-diagonal matrix elements of the Liouville operator iS1 - S2 introduced in the formalism. When one considers the line coupling for isotropic Raman Q lines where their initial and final rotational quantum numbers are identical, the derivations of off-diagonal elements do not require extra correlation functions of the Ŝ operator and their Fourier transforms except for those used in deriving diagonal elements. In contrast, the derivations for infrared P and R lines become more difficult because they require a lot of new correlation functions and their Fourier transforms. By introducing two dimensional correlation functions labeled by two tensor ranks and making variable changes to become even functions, the derivations only require the latters' two dimensional Fourier transforms evaluated at two modulation frequencies characterizing the averaged energy gap and the frequency detuning between the two coupled transitions. With the coordinate representation, it is easy to accurately derive these two dimensional correlation functions. Meanwhile, by using the sampling theory one is able to effectively evaluate their two dimensional Fourier transforms. Thus, the obstacles in considering the line coupling for P and R lines have been overcome. Numerical calculations have been carried out for the half-widths of both the isotropic Raman Q lines and the infrared P and R lines of C2H2 broadened by N2. In comparison with values derived from the RB formalism, new calculated values are significantly reduced and become closer to measurements.
Collapse
Affiliation(s)
- Q Ma
- NASA/Goddard Institute for Space Studies and Department of Applied Physics and Applied Mathematics, Columbia University, 2880 Broadway, New York, New York 10025, USA
| | - C Boulet
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS (UMR8214) et Université Paris-Sud Bât 350, Campus d'Orsay F-91405, France
| | - R H Tipping
- Department of Physics and Astronomy, University of Alabama, Tuscaloosa, Alabama 35487-0324, USA
| |
Collapse
|
5
|
Campbell HM, Havey DK. Pressure-broadening of water transitions near 7180 cm(-1) by helium isotopes. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2013; 109:232-238. [PMID: 23542497 DOI: 10.1016/j.saa.2013.01.099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Revised: 01/20/2013] [Accepted: 01/27/2013] [Indexed: 06/02/2023]
Abstract
In this study, pressure-broadening parameters for several H2O transitions near 7180 cm(-1) are obtained which describe collisions with (3)He and (4)He. The sensitivity of those parameters to choice of theoretical line profile (Galatry vs. Voigt) is investigated. H2O is an important species in atmospheric chemistry and astronomy. Because of this, basic fundamental research, which explores the nature of the H2O spectrum in the presence of different gases of varying physical properties, can provide useful reference data which can be applied in the fields of atmospheric and planetary remote sensing. Measurements were made using an intensity-modulated laser photoacoustic spectrometer. Results from the present work show that Galatry line profiles, with a constrained narrowing parameter, more accurately describe experimental spectra than Voigt profiles over a wide range of experimental pressure conditions. Average pressure-broadening parameters were found to be 0.0216 cm(-1)/atm and 0.0209 cm(-1)/atm for H2O in (3)He and (4)He, respectively, and were compared to a literature model for the mass-dependence of line broadening. Specific values were obtained for each transition with nominal combined uncertainties of 2-6%.
Collapse
Affiliation(s)
- H M Campbell
- Department of Chemistry and Biochemistry, James Madison University, MSC 4501, Harrisonburg, VA 22807, USA.
| | | |
Collapse
|
6
|
Ngo NH, Tran H, Gamache RR, Hartmann JM. Pressure effects on water vapour lines: beyond the Voigt profile. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2012; 370:2495-2508. [PMID: 22547229 DOI: 10.1098/rsta.2011.0272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
A short overview of recent results on the effects of pressure (collisions) regarding the shape of isolated infrared lines of water vapour is presented. The first part of this study considers the basic collisional quantities, which are the pressure-broadening and -shifting coefficients, central parameters of the Lorentzian (and Voigt) profile and thus of any sophisticated line-shape model. Through comparisons of measured values with semi-classical calculations, the influences of the molecular states (both rotational and vibrational) involved and of the temperature are analysed. This shows the relatively unusual behaviour of H(2)O broadening, with evidence of a significant vibrational dependence and the fact that the broadening coefficient (in cm(-1) atm(-1)) of some lines increases with temperature. In the second part of this study, line shapes beyond the Voigt model are considered, thus now taking 'velocity effects' into account. These include both the influence of collisionally induced velocity changes that lead to the so-called Dicke narrowing and the influence of the dependence of collisional parameters on the speed of the radiating molecule. Experimental evidence of deviations from the Voigt shape is presented and analysed. The interest of classical molecular dynamics simulations, to model velocity changes, together with semi-classical calculations of the speed-dependent collisional parameters for line-shape predictions from 'first principles', are discussed.
Collapse
Affiliation(s)
- N H Ngo
- Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), CNRS (UMR 7583), Institut Pierre-Simon Laplace, Université Paris Diderot, Université Paris Est Créteil, 94010 Créteil Cedex, France
| | | | | | | |
Collapse
|
7
|
Ma Q, Tipping R, Lavrentieva N. Theoretical studies of N2-broadened half-widths of H2O lines involving highjstates. Mol Phys 2012. [DOI: 10.1080/00268976.2011.646333] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
|
8
|
Ma Q, Tipping R, Lavrentieva N. Pair identity and smooth variation rules applicable for the spectroscopic parameters of H2O transitions involving high-Jstates. Mol Phys 2011. [DOI: 10.1080/00268976.2011.599343] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
9
|
Comparison of high-level post-Hartree–Fock and DFT methods on the calculation of interaction-induced electric properties of Kr–He. Chem Phys 2011. [DOI: 10.1016/j.chemphys.2011.03.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|