Nitrogen second positive system studied by electron induced fluorescence

Országh, J.; Danko, Marián; Ribar, Anita; Matejčík, Štefan

doi:10.1016/j.nimb.2011.10.031

Cited by 20 publications

(16 citation statements)

References 8 publications

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“…At the pressures used for our experiments polar water molecules form a deposit on the electrodes of the electron gun (Berman 1996) which causes a linear offset in the electron energy. To correct for this the energy of the electron beam was first absolutely calibrated by introducing a mixture of N2, helium, and H2O into the set up and by measuring the intensity profile of the N2 (C 3 Pu- The former has a sharp maximum at an electron energy of 14.1 eV (Országh et al 2012), the latter has a threshold at an electron energy of 23.736 eV (NIST 2015). We then measured the energy dependence of the intensity of the Hb emission for both the gas mixture and the pure H2O beam.…”

Section: Calibration Proceduresmentioning

confidence: 99%

Diagnostics of Collisions between Electrons and Water Molecules in Near-ultraviolet and Visible Wavelengths

Bodewits

Országh

Noonan

et al. 2019

ApJ

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We studied dissociation reactions of electron impact on water vapor for several fragment species at optical and near ultraviolet wavelengths (200 -850 nm). The resulting spectrum is dominated by the Hydrogen Balmer series, by the OH (A 2 Σ + -X 2 Π) band, and by the emission of ionic H2O + (A 2 A1 -X 2 B1) and OH + (A 3 Π -X 3 Σ -) band systems. Emission cross sections and reaction channel thresholds were determined for energies between 5 -100 eV.We find that electron impact dissociation of H2O results in an emission spectrum of the OH (A 2 Σ + -X 2 Π) band that is distinctly different than the emission spectra from other excitation mechanisms seen in planetary astronomy. We attribute the change to a strongly non-thermal population of rotational states seen in planetary astronomy. This difference can be utilized for remote probing of the contribution of different physical reactions in astrophysical environments.

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Section: Calibration Proceduresmentioning

confidence: 99%

Diagnostics of Collisions between Electrons and Water Molecules in Near-ultraviolet and Visible Wavelengths

Bodewits

Országh

Noonan

et al. 2019

ApJ

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“…18 The spectral peaks in the ultraviolet-visible (UV-Vis) range correspond to excited nitrogen. 22 In this work, a low level of Ar was supplied to the corona area with a flow rate of 1 to 2 L/min from 5 cm away to increase the ), and ozone (O 3 ) were observed in the OES, and those have been known to effectively inactivate microorganisms and to modify the surface. 11,[23][24][25][26] To substantiate the effects of nonthermal corona plasma for seed surface alteration, related to wettability enhancement, we exposed rice seeds to corona plasma for approximately 2 min.…”

Section: Resultsmentioning

confidence: 99%

Atmospheric Corona Discharge Plasma for Rice (Oryza sativa L.) Seed Surface Modification, Fungi Decontamination, and Shelf Life Extension

et al. 2020

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We demonstrate atmospheric corona plasma can modify rice (Oryza sativa L.) seed surface wettability and eliminate attached microorganisms at ambient temperatures, which can enhance germination and extend shelf life. High electric field strength up to 10 5 V/cm at the electrode tips is the critical factor for generating corona discharge plasma and, consequently, providing reactive oxygen and nitrogen species (RONS) via electron-induced impact ionization. We show that the reactive species and ions are primarily responsible for enhanced seed surface wettability via water imbibition (WI) and apparent contact angle (ACA) measurement. A scanning electron microscope was employed to confirm that the cold corona plasma treatment can decontaminate seedborne pathogenic fungi. Sterilized seeds with better surface wettability are more likely to germinate and yield higher quality seedlings. In addition, we demonstrate the potential use of the corona plasma process for seed storage extension and quality retention through accelerated aging germination and decreased moisture content. Germination of treated seed after passing accelerated aging process is approximately 90%, similar to that of unaged and untreated seeds.

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“…Electron impact excitation of methane (CH 4 ) was studied using a recently developed crossed beam apparatus in Bratislava [26]. A detailed schematic view of the apparatus is presented in figure 1.…”

Section: Methodsmentioning

confidence: 99%

“…We calibrated the electron energy scale by measuring the emission cross section of the (0,0) band of the second positive system of N 2 (C 3 u → B 3 g ) at 337 nm [26,29] and the He I (1s2p Two different measurement modes were used in the present study, (i) fluorescence spectra were recorded at fixed electron energies and (ii) the electron energy dependence of a specific transition was measured by setting the optical monochromator to transmit the corresponding wavelength. Apparent thresholds in the electron energy scans were deduced utilizing a fitting routine based on an exponential power law [14].…”

Section: Methodsmentioning

confidence: 99%

Electron impact excitation of methane: determination of appearance energies for dissociation products

Danko

Országh

Ďurian

et al. 2013

J. Phys. B: At. Mol. Opt. Phys.

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In this work, we present an experimental study of dissociative excitation of CH 4 utilizing a crossed electron molecular beam experiment. Methane was excited by nearly monochromatic electrons generated by a trochoidal electron monochromator. The dissociative products were identified on the basis of the emission spectra in the ultraviolet-visible (UV/VIS) spectral range. The excitation functions were recorded as the function of the electron energy for different emission bands of the fragments (Balmer series for H: n = 3,4 . . . 9→2, and moreover, CH: A 2 →X 2 , CH: B S 0 ). From the experimental data we have determined the threshold energies for excitation of particular fragments. Present experimental results indicate that the threshold energies for some dissociative excitation channels could be lower by ∼1-2 eV in comparison to earlier studies and indicate that different dissociative processes may be operative at the threshold than assumed in the former studies.

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Nitrogen second positive system studied by electron induced fluorescence

Cited by 20 publications

References 8 publications

Diagnostics of Collisions between Electrons and Water Molecules in Near-ultraviolet and Visible Wavelengths

Diagnostics of Collisions between Electrons and Water Molecules in Near-ultraviolet and Visible Wavelengths

Atmospheric Corona Discharge Plasma for Rice (Oryza sativa L.) Seed Surface Modification, Fungi Decontamination, and Shelf Life Extension

Electron impact excitation of methane: determination of appearance energies for dissociation products

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