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Pure rotational coherent anti-Stokes Raman spectroscopy of ethylene, experiments and modelling

Hosseinnia, Ali LU orcid ; Brackmann, Christian LU and Bengtsson, Per Erik LU orcid (2019) In Journal of Quantitative Spectroscopy and Radiative Transfer 234. p.24-31
Abstract

Rotational coherent anti-Stokes Raman spectroscopy (CARS) is an established diagnostic technique for temperature and concentration measurements in combustion-related experiments. CARS has mainly been applied on di- and tri-atomics with linear molecular symmetry, for which good agreement is achieved between experimental and theoretical spectra. Hydrocarbons have so far been less attractive for rotational CARS studies, partly because of their complex molecular symmetries making it challenging to obtain molecular parameters necessary for a successful modeling. Nevertheless, in this work we have studied the asymmetric top molecule ethylene (C2H4) using rotational CARS through experiments and theoretical modelling.... (More)

Rotational coherent anti-Stokes Raman spectroscopy (CARS) is an established diagnostic technique for temperature and concentration measurements in combustion-related experiments. CARS has mainly been applied on di- and tri-atomics with linear molecular symmetry, for which good agreement is achieved between experimental and theoretical spectra. Hydrocarbons have so far been less attractive for rotational CARS studies, partly because of their complex molecular symmetries making it challenging to obtain molecular parameters necessary for a successful modeling. Nevertheless, in this work we have studied the asymmetric top molecule ethylene (C2H4) using rotational CARS through experiments and theoretical modelling. Experimental spectra have been recorded at temperatures between 293 K and 804 K, and theoretical spectra have been calculated with a novel method for which the crucial temperature-dependent linewidth parameters were determined by comparison of experimental and theoretically calculated spectra. Line-mixing effects and temperature dependence of the isolated linewidths were studied using a semi-classical approach considering an exponential gap law and a scaling law. Subsequently, theoretically calculated spectra were used to evaluate the temperatures of the experimental spectra for validation of the method. The evaluated temperatures were in good agreement with thermocouple temperatures with differences up to ±7 K. Hence, this work not only investigates the potential of using rotational CARS on ethylene for diagnostic purposes, but also expands the applicability of the technique to a whole new class of molecules with asymmetric-top molecular symmetry.

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publication status
published
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in
Journal of Quantitative Spectroscopy and Radiative Transfer
volume
234
pages
8 pages
publisher
Elsevier
external identifiers
  • scopus:85066786625
ISSN
0022-4073
DOI
10.1016/j.jqsrt.2019.05.022
language
English
LU publication?
yes
id
5cc0fd4b-e41e-4747-a30d-2cb8126a0be6
date added to LUP
2019-06-24 15:11:05
date last changed
2022-04-26 02:12:13
@article{5cc0fd4b-e41e-4747-a30d-2cb8126a0be6,
  abstract     = {{<p>Rotational coherent anti-Stokes Raman spectroscopy (CARS) is an established diagnostic technique for temperature and concentration measurements in combustion-related experiments. CARS has mainly been applied on di- and tri-atomics with linear molecular symmetry, for which good agreement is achieved between experimental and theoretical spectra. Hydrocarbons have so far been less attractive for rotational CARS studies, partly because of their complex molecular symmetries making it challenging to obtain molecular parameters necessary for a successful modeling. Nevertheless, in this work we have studied the asymmetric top molecule ethylene (C<sub>2</sub>H<sub>4</sub>) using rotational CARS through experiments and theoretical modelling. Experimental spectra have been recorded at temperatures between 293 K and 804 K, and theoretical spectra have been calculated with a novel method for which the crucial temperature-dependent linewidth parameters were determined by comparison of experimental and theoretically calculated spectra. Line-mixing effects and temperature dependence of the isolated linewidths were studied using a semi-classical approach considering an exponential gap law and a scaling law. Subsequently, theoretically calculated spectra were used to evaluate the temperatures of the experimental spectra for validation of the method. The evaluated temperatures were in good agreement with thermocouple temperatures with differences up to ±7 K. Hence, this work not only investigates the potential of using rotational CARS on ethylene for diagnostic purposes, but also expands the applicability of the technique to a whole new class of molecules with asymmetric-top molecular symmetry.</p>}},
  author       = {{Hosseinnia, Ali and Brackmann, Christian and Bengtsson, Per Erik}},
  issn         = {{0022-4073}},
  language     = {{eng}},
  pages        = {{24--31}},
  publisher    = {{Elsevier}},
  series       = {{Journal of Quantitative Spectroscopy and Radiative Transfer}},
  title        = {{Pure rotational coherent anti-Stokes Raman spectroscopy of ethylene, experiments and modelling}},
  url          = {{http://dx.doi.org/10.1016/j.jqsrt.2019.05.022}},
  doi          = {{10.1016/j.jqsrt.2019.05.022}},
  volume       = {{234}},
  year         = {{2019}},
}