A rotational Raman study under non-thermal conditions in a pulsed CO2 glow discharge

B.L.M. Klarenaar, M. Grofulović, A.S. Morillo-Candas, D.C.M. van den Bekerom, M.A. Damen, M.C.M. van de Sanden, O. Guaitella, R. Engeln

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The implementation of in situ rotational Raman spectroscopy is realized for a pulsed glow discharge in CO2 in the mbar range and is used to study the rotational temperature and molecular number densities of CO2, CO, and O2. The polarizability anisotropy of these molecules is required for extracting number densities from the recorded spectra and is determined for incident photons of 532 nm. The spatiotemporally-resolved measurements are performed in the same reactor and at equal discharge conditions (5-10 ms on-off cycle, 50 mA plasma current, 6.7 mbar pressure) as in recently published work employing in situ Fourier transform infrared (FTIR) spectroscopy. The rotational temperature ranges from 394 to 809 K from start to end of the discharge pulse and is constant over the length of the reactor. The discharge is demonstrated to be spatially uniform in gas composition, with a CO2 conversion factor of 0.15 ± 0.02. Rotational temperatures and molecular composition agree well with the FTIR results, while the spatial uniformity confirms the assumption made for the FTIR analysis of a homogeneous medium over the line-of-sight of absorption. Furthermore, the rotational Raman spectra of CO2 are related to vibrational temperatures through the vibrationally averaged nuclear spin degeneracy, which is expressed in the intensity ratio between even and odd numbered Raman peaks. The elevation of the odd averaged degeneracy above thermal conditions agrees well with the elevation of vibrational temperatures of CO2, acquired in the FTIR study.

Originele taal-2Engels
Artikelnummer045009
Aantal pagina's12
TijdschriftPlasma Sources Science and Technology
Volume27
Nummer van het tijdschrift4
DOI's
StatusGepubliceerd - 25 apr 2018

Vingerafdruk

glow discharges
reactors
temperature
plasma currents
gas composition
rotational spectra
nuclear spin
line of sight
Raman spectroscopy
infrared spectroscopy
Raman spectra
anisotropy
cycles
photons
pulses
molecules

Citeer dit

Klarenaar, B.L.M. ; Grofulović, M. ; Morillo-Candas, A.S. ; van den Bekerom, D.C.M. ; Damen, M.A. ; van de Sanden, M.C.M. ; Guaitella, O. ; Engeln, R. / A rotational Raman study under non-thermal conditions in a pulsed CO2 glow discharge. In: Plasma Sources Science and Technology. 2018 ; Vol. 27, Nr. 4.
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title = "A rotational Raman study under non-thermal conditions in a pulsed CO2 glow discharge",
abstract = "The implementation of in situ rotational Raman spectroscopy is realized for a pulsed glow discharge in CO2 in the mbar range and is used to study the rotational temperature and molecular number densities of CO2, CO, and O2. The polarizability anisotropy of these molecules is required for extracting number densities from the recorded spectra and is determined for incident photons of 532 nm. The spatiotemporally-resolved measurements are performed in the same reactor and at equal discharge conditions (5-10 ms on-off cycle, 50 mA plasma current, 6.7 mbar pressure) as in recently published work employing in situ Fourier transform infrared (FTIR) spectroscopy. The rotational temperature ranges from 394 to 809 K from start to end of the discharge pulse and is constant over the length of the reactor. The discharge is demonstrated to be spatially uniform in gas composition, with a CO2 conversion factor of 0.15 ± 0.02. Rotational temperatures and molecular composition agree well with the FTIR results, while the spatial uniformity confirms the assumption made for the FTIR analysis of a homogeneous medium over the line-of-sight of absorption. Furthermore, the rotational Raman spectra of CO2 are related to vibrational temperatures through the vibrationally averaged nuclear spin degeneracy, which is expressed in the intensity ratio between even and odd numbered Raman peaks. The elevation of the odd averaged degeneracy above thermal conditions agrees well with the elevation of vibrational temperatures of CO2, acquired in the FTIR study.",
keywords = "Carbon dioxide plasma, glow discharge, molecular composition, nuclear spin degeneracy, polarizability anisotropy, rotational Raman spectroscopy",
author = "B.L.M. Klarenaar and M. Grofulović and A.S. Morillo-Candas and {van den Bekerom}, D.C.M. and M.A. Damen and {van de Sanden}, M.C.M. and O. Guaitella and R. Engeln",
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A rotational Raman study under non-thermal conditions in a pulsed CO2 glow discharge. / Klarenaar, B.L.M.; Grofulović, M.; Morillo-Candas, A.S.; van den Bekerom, D.C.M.; Damen, M.A.; van de Sanden, M.C.M.; Guaitella, O.; Engeln, R.

In: Plasma Sources Science and Technology, Vol. 27, Nr. 4, 045009, 25.04.2018.

Onderzoeksoutput: Bijdrage aan tijdschriftTijdschriftartikelAcademicpeer review

TY - JOUR

T1 - A rotational Raman study under non-thermal conditions in a pulsed CO2 glow discharge

AU - Klarenaar, B.L.M.

AU - Grofulović, M.

AU - Morillo-Candas, A.S.

AU - van den Bekerom, D.C.M.

AU - Damen, M.A.

AU - van de Sanden, M.C.M.

AU - Guaitella, O.

AU - Engeln, R.

PY - 2018/4/25

Y1 - 2018/4/25

N2 - The implementation of in situ rotational Raman spectroscopy is realized for a pulsed glow discharge in CO2 in the mbar range and is used to study the rotational temperature and molecular number densities of CO2, CO, and O2. The polarizability anisotropy of these molecules is required for extracting number densities from the recorded spectra and is determined for incident photons of 532 nm. The spatiotemporally-resolved measurements are performed in the same reactor and at equal discharge conditions (5-10 ms on-off cycle, 50 mA plasma current, 6.7 mbar pressure) as in recently published work employing in situ Fourier transform infrared (FTIR) spectroscopy. The rotational temperature ranges from 394 to 809 K from start to end of the discharge pulse and is constant over the length of the reactor. The discharge is demonstrated to be spatially uniform in gas composition, with a CO2 conversion factor of 0.15 ± 0.02. Rotational temperatures and molecular composition agree well with the FTIR results, while the spatial uniformity confirms the assumption made for the FTIR analysis of a homogeneous medium over the line-of-sight of absorption. Furthermore, the rotational Raman spectra of CO2 are related to vibrational temperatures through the vibrationally averaged nuclear spin degeneracy, which is expressed in the intensity ratio between even and odd numbered Raman peaks. The elevation of the odd averaged degeneracy above thermal conditions agrees well with the elevation of vibrational temperatures of CO2, acquired in the FTIR study.

AB - The implementation of in situ rotational Raman spectroscopy is realized for a pulsed glow discharge in CO2 in the mbar range and is used to study the rotational temperature and molecular number densities of CO2, CO, and O2. The polarizability anisotropy of these molecules is required for extracting number densities from the recorded spectra and is determined for incident photons of 532 nm. The spatiotemporally-resolved measurements are performed in the same reactor and at equal discharge conditions (5-10 ms on-off cycle, 50 mA plasma current, 6.7 mbar pressure) as in recently published work employing in situ Fourier transform infrared (FTIR) spectroscopy. The rotational temperature ranges from 394 to 809 K from start to end of the discharge pulse and is constant over the length of the reactor. The discharge is demonstrated to be spatially uniform in gas composition, with a CO2 conversion factor of 0.15 ± 0.02. Rotational temperatures and molecular composition agree well with the FTIR results, while the spatial uniformity confirms the assumption made for the FTIR analysis of a homogeneous medium over the line-of-sight of absorption. Furthermore, the rotational Raman spectra of CO2 are related to vibrational temperatures through the vibrationally averaged nuclear spin degeneracy, which is expressed in the intensity ratio between even and odd numbered Raman peaks. The elevation of the odd averaged degeneracy above thermal conditions agrees well with the elevation of vibrational temperatures of CO2, acquired in the FTIR study.

KW - Carbon dioxide plasma

KW - glow discharge

KW - molecular composition

KW - nuclear spin degeneracy

KW - polarizability anisotropy

KW - rotational Raman spectroscopy

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U2 - 10.1088/1361-6595/aabab6

DO - 10.1088/1361-6595/aabab6

M3 - Article

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VL - 27

JO - Plasma Sources Science and Technology

JF - Plasma Sources Science and Technology

SN - 0963-0252

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