Nonstationary processes in matrix-isolated methane probed by optical and current emission spectroscopy

Savchenko, E. V.; Khyzhniy, I. V.; Uyutnov, S. A.; Bludov, M. A.; Bondybey, V. E.

doi:10.1016/j.molstruc.2020.128803

Cited by 7 publications

(5 citation statements)

References 54 publications

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“…Our study of the dose dependences of the emission of H atoms and CH radicals performed at low temperatures showed a sharply nonmonotonic behavior of these emissions. As follows from the analysis of BR reactions (4), ( 7), ( 8) and (10), CH 3 radicals remain the main source of CH radical formation upon excitation by free excitons of the matrix; so, the conclusion that CH is a CH 3 marker [55] remains valid. Figure 6 shows the dose dependencies of the H and CH emissions measured simultaneously with the pressure in the experimental chamber.…”

Section: Resultsmentioning

confidence: 99%

“…To get more insight into the phenomenon, the matrix isolation method was introduced, in combination with a set of emission spectroscopy methods [53][54][55]. It should be noted that in contrast to pure methane and mixtures of methane with other molecular gases of astrophysical interest, there are only a few studies performed in matrices of rare gases [56][57][58].…”

Section: Introductionmentioning

confidence: 99%

“…Below, we briefly summarize the results of our previous studies of radiation effects induced by an electron beam in Ar matrices doped with CH 4 [53][54][55]59]. In the cathodoluminescence (CL) spectra, the following products of radiation-induced methane transformation were recorded: H, CH and C. It has been shown that because of the small penetration depth of electrons, the bulk of the matrix is excited preferentially by photons of the matrix with an energy of 9.8 eV (the most intense emission band of the self-trapped excitons); in other words, "internal photolysis" occurs.…”

Section: Introductionmentioning

confidence: 99%

“…In the cathodoluminescence (CL) spectra, the following products of radiation-induced methane transformation were recorded: H, CH and C. It has been shown that because of the small penetration depth of electrons, the bulk of the matrix is excited preferentially by photons of the matrix with an energy of 9.8 eV (the most intense emission band of the self-trapped excitons); in other words, "internal photolysis" occurs. Analysis of the efficiency of different channels of methane transformation under these photons and neutralization reactions indicated that the CH radical can be considered a signature of the CH 3 radicals [55]. Monitoring of the so-called nonstationary luminescence (NsL), viz.…”

Section: Introductionmentioning

confidence: 99%

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Matrix-Assisted Processes in CH4-Doped Ar Ices Irradiated with an Electron Beam

Bludov,

Khyzhniy,

Uyutnov

et al. 2023

Methane

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The relaxation processes induced by exposure of the Ar matrices doped with CH4 (0.1–10%) to an electron beam were studied with a focus on the dynamics of radiolysis products—H atoms, H2 molecules, CH radicals, and energy transfer processes. Three channels of energy transfer to dopant and radiolysis products were discussed, including free charge carriers, free excitons and photons from the “intrinsic source” provided by the emission of the self-trapped excitons. Radiolysis products along with the total yield of desorbing particles were monitored in a correlated manner. Analysis of methane transformation reactions induced by free excitons showed that the CH radical can be considered a marker of the CH3 species. The competition between exciton self-trapping and energy transfer to the dopant and radiolysis products has been demonstrated. A nonlinear concentration behavior of the H atoms in doped Ar matrices has been established. Real-time correlated monitoring of optical emissions (H atom and CH3 radicals), particle ejection, and temperature revealed a nonmonotonic behavior of optical yields with a strong luminescence flash after almost an hour of exposure, which correlated with the explosive pulse of particle ejection and temperature. The connection of this phenomenon with the processes of energy transfer and recombination reactions has been established. It is shown that the delayed explosive ejection of particles is driven by both the recombination of H atoms and CH3 radicals. This occurs after their accumulation to a critical concentration in matrices at a CH4 content C ≥ 1%.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Matrix-Assisted Processes in CH4-Doped Ar Ices Irradiated with an Electron Beam

Bludov,

Khyzhniy,

Uyutnov

et al. 2023

Methane

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“…It is possible that the gases released, during radiation treatment, remain trapped leading to cracks or rupture especially in case of vitreous or partially crystalline molecules or polymers. The trapped gases raise the strain in the irradiated specimen which can be released with post irradiation heat treatment [60,61].…”

Section: Gas Evolutionmentioning

confidence: 99%

Electron Beam Induced Tailoring of Electrical Characteristics of Organic Semiconductor Films

et al. 2020

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Tailoring the characteristics of organic semiconductors including molecular semiconductor and conducting polymers is the frontline area of research for improving the performance of organic electronic devices. Electron beam treatment has been established as one of the easiest method in comparison to others like chemical doping, thermal processing, ozonolysis, UV and other ionizing radiation treatment, to tune the physico-chemical properties of organic semiconductors. High energy electron beam (EB) generated from an accelerators impinges energy to the material and causes several phenomena including doping, crosslinking, chain degradation, gas evolution, molecular structural modifications, oxidation and unsaturation. Such modifications lead to variation in electrical characteristics and consequently affect the overall device performances. In the present review we have focused on the different interaction processes of EB with organic semiconductors and its implications to tailor the performance of device comprising of it mainly gas sensors, field effect transistors, thermoelectric power generators and radiation dosimeters.

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