title: Radiation effects in solid nitrogen and nitrogen-containing matrices: fingerprints of N₄⁺ species.
abstract: The radiation effects and relaxation processes in solid N2 and N2-doped Ne matrices, preirradiated by an electron beam, have been studied in the temperature range of 5-40 and 5-15 K, respectively. The study was performed using luminescence methods: cathodoluminescence CL and developed by our group nonstationary luminescence NsL, as well as optical and current activation spectroscopy methods: spectrally resolved thermally stimulated luminescence TSL and exoelectron emission TSEE. An appreciable accumulation of N radicals, N(+), N2(+) ions, and trapped electrons is found in nitrogen-containing Ne matrices. Neutralization reactions were shown to dominate relaxation scenario in the low-temperature range, while at higher temperatures diffusion-controlled reactions of neutral species contribute. It was conceived that in α-phase of solid N2, the dimerization reaction (N2(+) + N2 → N4(+)) proceeds: "hole self-trapping". Tetranitrogen cation N4(+) manifests itself by the dissociative recombination reaction with electron: N4(+) + e(-) → N2*(a'(1)Σ(u)(-)) + N2 → N2 + N2 + hν. In line with this assumption, we observed a growth of the a'(1)Σ(u)(-) → X(1)Σ(g)(+) transition intensity with an exposure time in CL spectra and the emergence of this emission in the course of electron detrapping on sample heating in the TSL and NsL experiments.
authors.affiliation: †Institute for Low Temperature Physics and Engineering NASU, 61103 Kharkov, Ukraine.
authors.forename: Elena V
authors.initials: EV
authors.lastname: Savchenko
authors.affiliation: †Institute for Low Temperature Physics and Engineering NASU, 61103 Kharkov, Ukraine.
authors.forename: Ivan V
authors.initials: IV
authors.lastname: Khyzhniy
authors.affiliation: †Institute for Low Temperature Physics and Engineering NASU, 61103 Kharkov, Ukraine.
authors.forename: Sergey A
authors.initials: SA
authors.lastname: Uyutnov
authors.affiliation: †Institute for Low Temperature Physics and Engineering NASU, 61103 Kharkov, Ukraine.
authors.forename: Andrey P
authors.initials: AP
authors.lastname: Barabashov
authors.affiliation: ‡Department Chemie, Lehrstuhl II für Physikalische Chemie, Technische Universität München, 85747 Garching, Germany.
authors.forename: Galina B
authors.initials: GB
authors.lastname: Gumenchuk
authors.affiliation: §Institut für Ionenphysik und Angewandte Physik Leopold-Franzens-Universität Innsbruck, 6020 Innsbruck, Austria.
authors.forename: Martin K
authors.initials: MK
authors.lastname: Beyer
authors.affiliation: ∥Helmholtz Zentrum Dresden-Rossendorf, 01328 Dresden, Germany.
authors.forename: Alexey N
authors.initials: AN
authors.lastname: Ponomaryov
authors.affiliation: ‡Department Chemie, Lehrstuhl II für Physikalische Chemie, Technische Universität München, 85747 Garching, Germany.
authors.forename: Vladimir E
authors.initials: VE
authors.lastname: Bondybey