Measurement of collisional quenching rate of nitrogen states N2(C 3Πu, v = 0) and

Valk, F. van der; Aints, M.; Paris, P.; Plank, Toomas; Maksimov, J; Tamm, Artur

doi:10.1088/0022-3727/43/38/385202

Cited by 78 publications

(61 citation statements)

References 60 publications

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“…The lifetime of N 2 (C,0) state is determined by the radiative decay and by quenching in collisions with the host gas particles and electrons. Radiative decay frequency of N 2 (C,0) state is ca s -1 [23]. (4) 70% of OH(A) is produced in the vibrational state v=0, ca 25% -in the state v=1 and 5% -in the state v=2.…”

Section: Determination Of Rotational Temperaturementioning

confidence: 99%

Rotational temperatures of N₂(C,0) and OH(A,0) as gas temperature estimates in the middle pressure Ar/O₂ discharge

Raud¹,

Laan²,

Jõgi³

2011

J. Phys. D: Appl. Phys.

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Abstract. Radiative transitions N 2 (C-B,0-0) and OH(A-X,0-0) were used in order to estimate rotational temperatures of N 2 (C,0) and OH(A,0) in the middle pressure Ar / 0.5% O 2 RF discharge. N 2 (C,0) and OH(A,0) rotational temperature dependence on power density was determined and quenching / rotational relaxation frequencies of N 2 (C,0) and OH(A,0) was calculated. It was found that at our conditions rotational temperature of OH(A,0) can be used for estimation of gas temperature while N 2 (C,0) rotational temperature overestimates the gas temperature.

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Section: Determination Of Rotational Temperaturementioning

confidence: 99%

Rotational temperatures of N₂(C,0) and OH(A,0) as gas temperature estimates in the middle pressure Ar/O₂ discharge

Raud¹,

Laan²,

Jõgi³

2011

J. Phys. D: Appl. Phys.

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“…35 The other loss mechanisms can usually be neglected. The most important excitation processes for the N 2 (C 3 P u ) state are electron excitation from the ground state N 2 (X 1 R g þ ) (10), 38 Penning excitation by argon metastable atoms Ar( 3 P 2 ) (11) (Ref.…”

Section: B Argon Metastable Lifetimesmentioning

confidence: 99%

“…[35][36][37][38] The excitation coefficients for reaction (10) and for reactions (11) and (12) are well known. Based on the measured argon metastable density n m Ar ¼ (0.1-2.5)10 10 cm À3 and the previously estimated electron density n e ¼ 2 Â 10 10 cm À3 , it can be shown that reaction (11) can be neglected by comparing to Eq.…”

Section: B Argon Metastable Lifetimesmentioning

confidence: 99%

Argon metastable dynamics and lifetimes in a direct current microdischarge

Stefanović

Kuschel

Schröter

et al. 2014

Journal of Applied Physics

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Absolute nitrogen atom density measurements by two-photon laser-induced fluorescence spectroscopy in atmospheric pressure dielectric barrier discharges of pure nitrogen Study of the Ar metastable atom population in a hollow cathode discharge by means of a hybrid model and spectrometric measurementsIn this paper we study the properties of a pulsed dc microdischarge with the continuous flow of argon. Argon metastable lifetimes are measured by tunable diode laser absorption spectroscopy (TDLAS) and are compared with calculated values which yield information about excitation and de-excitation processes. By increasing the gas flow-rate about 5 times from 10 to 50 sccm, the Ar m lifetime increases from 1 to 5 ls due to the reduction of metastable quenching with gas impurities. Optical emission spectroscopy reveals nitrogen and water molecules as the main gas impurities. The estimated N 2 density [N 2 ] ¼ 0.1% is too low to explain the measured metastable lifetimes. Water impurity was found to be the main de-excitation source of argon metastable atoms due to high quenching coefficients. The water impurity level of [H 2 O] ¼ 0.15% to 1% is sufficient to bring calculated metastable lifetimes in line with experiments. The maximum value of water content in the discharge compared to the argon atoms is estimated to approximately 6%, due to the large surface to volume ratio of the microdischarge. The current pulse releases the water molecules from the electrode surface and they are either re-adsorbed in the time between 0.4 ms for [H 2 O] ¼ 1% and 2.6 ms for [H 2 O] ¼ 0.15% or pumped out of the discharge with the speed equal to the gas flowrate. Depending on its partial pressure, the water impurity re-adsorption time is of the order of magnitude or less then the argon gas residence time. V C 2014 AIP Publishing LLC.

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“…All rate constants as well as the lifetimes τ 0 of the excited states were taken from [48] except for k B conv , which was taken from [44]. All rate constants as well as the lifetimes τ 0 of the excited states were taken from [48] except for k B conv , which was taken from [44].…”

Section: Gas Temperature and Reduced Electric Fieldmentioning

confidence: 99%

Impact of Electrode Design, Supply Voltage and Interelectrode Distance on Safety Aspects and Characteristics of a Medical DBD Plasma Source

Helmke

Wandke

Mahmoodzada

et al. 2013

Contrib. Plasma Phys.

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In the frame of plasma source development for dermatological applications in the field of plasma medicine, operational safety of the devices is of superior priority. For sources based on the concept of dielectric barrier discharges (DBD), electric potentials with amplitudes in the range of some kV are arranged in close proximity to the skin of patients, wherein dielectric strength of the electrodes and leakage currents are crucial for electrical applicability. In this work, ceramic electrodes of 10 mm in diameter and varying ceramic thickness are operated at input powers up to 300 mW against non-biological counter electrodes. In a combined experimental and numerical approach, electric fields inside the ceramic are determined, whereas values are well below the dielectric strength of the material. The spectrally weighted plasma emission is within limit values of exposure to human skin as long as daily treatment does not exceeded 7 h. Neutral gas temperatures of up to 310 K are determined which underline the minor thermal impact of the plasma exposure. In contrast, values for reduced electric fields are of the order of some hundred Townsend and thus the electrons can initiate various secondary effects such as chemical reaction chains. Consequently, ozone concentrations in the discharges are quantified between 230 ppm and 1140 ppm in close proximity to the actual discharge volume and the results are discussed in the frame of risk assessment for therapeutic applications in dermatology.

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Measurement of collisional quenching rate of nitrogen states N₂(C ³Π_u, v = 0) and

Cited by 78 publications

References 60 publications

Rotational temperatures of N₂(C,0) and OH(A,0) as gas temperature estimates in the middle pressure Ar/O₂ discharge

Rotational temperatures of N₂(C,0) and OH(A,0) as gas temperature estimates in the middle pressure Ar/O₂ discharge

Argon metastable dynamics and lifetimes in a direct current microdischarge

Impact of Electrode Design, Supply Voltage and Interelectrode Distance on Safety Aspects and Characteristics of a Medical DBD Plasma Source

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Measurement of collisional quenching rate of nitrogen states N2(C 3Πu, v = 0) and

Cited by 78 publications

References 60 publications

Rotational temperatures of N2(C,0) and OH(A,0) as gas temperature estimates in the middle pressure Ar/O2 discharge

Rotational temperatures of N2(C,0) and OH(A,0) as gas temperature estimates in the middle pressure Ar/O2 discharge

Argon metastable dynamics and lifetimes in a direct current microdischarge

Impact of Electrode Design, Supply Voltage and Interelectrode Distance on Safety Aspects and Characteristics of a Medical DBD Plasma Source

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Product

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Measurement of collisional quenching rate of nitrogen states N₂(C ³Π_u, v = 0) and

Rotational temperatures of N₂(C,0) and OH(A,0) as gas temperature estimates in the middle pressure Ar/O₂ discharge

Rotational temperatures of N₂(C,0) and OH(A,0) as gas temperature estimates in the middle pressure Ar/O₂ discharge