A rotational Raman study under non-thermal conditions in pulsed CO2-N-2 and CO2-O-2 glow discharges

M. Grofulovic (Corresponding author), B.L.M. Klarenaar, O. Guaitella, V. Guerra, R. Engeln

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This work employs in situ rotational Raman spectroscopy to study the effect of N2 and O2 addition to CO2 in pulsed glow discharges in the mbar range. The spatiotemporally resolved measurements are performed in CO2 and 25%, 50% and 75% of N2 or O2 admixture, in a 5–10 ms on-off cycle, 50 mA plasma current and 6.7 mbar total pressure. The rotational temperature profile is not affected by adding N2, ranging from 400 to 850 K from start to end of the discharge pulse, while the addition of O2 decreases the temperature at corresponding time points. Molecular number densities of CO2, CO, O2 and N2 are determined, showing the spatial homogeneity along the axis of the reactor and uniformity during the cycle. The measurements in the N2 containing mixtures show that CO2 conversion factor α increases from 0.15 to 0.33 when the content of N2 is increased from 0% to 75%, demonstrating the potential of N2 addition to enhance the vibrational pumping of CO2 and its beneficial effect on CO2 dissociation. Furthermore, the influence of admixtures on CO2 vibrations is examined by analysing the vibrationally averaged nuclear spin degeneracy. The difference between the fitted odd averaged degeneracy and the calculated odd degeneracy assuming thermal conditions increases with the addition of N2, demonstrating the growth of vibrational temperatures in CO2. On the other hand, the addition of O2 leads to a decrease of α, which might be attributed to quenched vibrations of CO2, and/or to the influence of the back reaction in the presence of O2.
Originele taal-2Engels
Artikelnummer045014
Aantal pagina's9
TijdschriftPlasma Sources Science and Technology
Volume28
Nummer van het tijdschrift4
DOI's
StatusGepubliceerd - 24 apr 2019

Citeer dit

@article{84ab61b0ede44aacb552847d4c60420a,
title = "A rotational Raman study under non-thermal conditions in pulsed CO2-N-2 and CO2-O-2 glow discharges",
abstract = "This work employs in situ rotational Raman spectroscopy to study the effect of N2 and O2 addition to CO2 in pulsed glow discharges in the mbar range. The spatiotemporally resolved measurements are performed in CO2 and 25{\%}, 50{\%} and 75{\%} of N2 or O2 admixture, in a 5–10 ms on-off cycle, 50 mA plasma current and 6.7 mbar total pressure. The rotational temperature profile is not affected by adding N2, ranging from 400 to 850 K from start to end of the discharge pulse, while the addition of O2 decreases the temperature at corresponding time points. Molecular number densities of CO2, CO, O2 and N2 are determined, showing the spatial homogeneity along the axis of the reactor and uniformity during the cycle. The measurements in the N2 containing mixtures show that CO2 conversion factor α increases from 0.15 to 0.33 when the content of N2 is increased from 0{\%} to 75{\%}, demonstrating the potential of N2 addition to enhance the vibrational pumping of CO2 and its beneficial effect on CO2 dissociation. Furthermore, the influence of admixtures on CO2 vibrations is examined by analysing the vibrationally averaged nuclear spin degeneracy. The difference between the fitted odd averaged degeneracy and the calculated odd degeneracy assuming thermal conditions increases with the addition of N2, demonstrating the growth of vibrational temperatures in CO2. On the other hand, the addition of O2 leads to a decrease of α, which might be attributed to quenched vibrations of CO2, and/or to the influence of the back reaction in the presence of O2.",
keywords = "carbon dioxide plasma, glow discharge, vibrational excitation, rotational Raman spectroscopy",
author = "M. Grofulovic and B.L.M. Klarenaar and O. Guaitella and V. Guerra and R. Engeln",
year = "2019",
month = "4",
day = "24",
doi = "10.1088/1361-6595/ab1240",
language = "English",
volume = "28",
journal = "Plasma Sources Science and Technology",
issn = "0963-0252",
publisher = "Institute of Physics",
number = "4",

}

A rotational Raman study under non-thermal conditions in pulsed CO2-N-2 and CO2-O-2 glow discharges. / Grofulovic, M. (Corresponding author); Klarenaar, B.L.M.; Guaitella, O.; Guerra, V.; Engeln, R.

In: Plasma Sources Science and Technology, Vol. 28, Nr. 4, 045014, 24.04.2019.

Onderzoeksoutput: Bijdrage aan tijdschriftTijdschriftartikelAcademicpeer review

TY - JOUR

T1 - A rotational Raman study under non-thermal conditions in pulsed CO2-N-2 and CO2-O-2 glow discharges

AU - Grofulovic, M.

AU - Klarenaar, B.L.M.

AU - Guaitella, O.

AU - Guerra, V.

AU - Engeln, R.

PY - 2019/4/24

Y1 - 2019/4/24

N2 - This work employs in situ rotational Raman spectroscopy to study the effect of N2 and O2 addition to CO2 in pulsed glow discharges in the mbar range. The spatiotemporally resolved measurements are performed in CO2 and 25%, 50% and 75% of N2 or O2 admixture, in a 5–10 ms on-off cycle, 50 mA plasma current and 6.7 mbar total pressure. The rotational temperature profile is not affected by adding N2, ranging from 400 to 850 K from start to end of the discharge pulse, while the addition of O2 decreases the temperature at corresponding time points. Molecular number densities of CO2, CO, O2 and N2 are determined, showing the spatial homogeneity along the axis of the reactor and uniformity during the cycle. The measurements in the N2 containing mixtures show that CO2 conversion factor α increases from 0.15 to 0.33 when the content of N2 is increased from 0% to 75%, demonstrating the potential of N2 addition to enhance the vibrational pumping of CO2 and its beneficial effect on CO2 dissociation. Furthermore, the influence of admixtures on CO2 vibrations is examined by analysing the vibrationally averaged nuclear spin degeneracy. The difference between the fitted odd averaged degeneracy and the calculated odd degeneracy assuming thermal conditions increases with the addition of N2, demonstrating the growth of vibrational temperatures in CO2. On the other hand, the addition of O2 leads to a decrease of α, which might be attributed to quenched vibrations of CO2, and/or to the influence of the back reaction in the presence of O2.

AB - This work employs in situ rotational Raman spectroscopy to study the effect of N2 and O2 addition to CO2 in pulsed glow discharges in the mbar range. The spatiotemporally resolved measurements are performed in CO2 and 25%, 50% and 75% of N2 or O2 admixture, in a 5–10 ms on-off cycle, 50 mA plasma current and 6.7 mbar total pressure. The rotational temperature profile is not affected by adding N2, ranging from 400 to 850 K from start to end of the discharge pulse, while the addition of O2 decreases the temperature at corresponding time points. Molecular number densities of CO2, CO, O2 and N2 are determined, showing the spatial homogeneity along the axis of the reactor and uniformity during the cycle. The measurements in the N2 containing mixtures show that CO2 conversion factor α increases from 0.15 to 0.33 when the content of N2 is increased from 0% to 75%, demonstrating the potential of N2 addition to enhance the vibrational pumping of CO2 and its beneficial effect on CO2 dissociation. Furthermore, the influence of admixtures on CO2 vibrations is examined by analysing the vibrationally averaged nuclear spin degeneracy. The difference between the fitted odd averaged degeneracy and the calculated odd degeneracy assuming thermal conditions increases with the addition of N2, demonstrating the growth of vibrational temperatures in CO2. On the other hand, the addition of O2 leads to a decrease of α, which might be attributed to quenched vibrations of CO2, and/or to the influence of the back reaction in the presence of O2.

KW - carbon dioxide plasma

KW - glow discharge

KW - vibrational excitation

KW - rotational Raman spectroscopy

U2 - 10.1088/1361-6595/ab1240

DO - 10.1088/1361-6595/ab1240

M3 - Article

VL - 28

JO - Plasma Sources Science and Technology

JF - Plasma Sources Science and Technology

SN - 0963-0252

IS - 4

M1 - 045014

ER -