title: Highly efficient exciplex formation via radical ion pair recombination in X-irradiated alkane solutions for luminophores with short fluorescence lifetimes.
abstract: X-irradiation of alkane solutions of N,N-dimethylaniline with various organic luminophores produces characteristic emission bands ascribed to the corresponding exciplexes. In contrast to optical generation, which requires diffusion-controlled quenching of excited states, an additional channel of exciplex formation via irreversible recombination of radical ion pairs is operative here, which produces exciplexes in solution with high efficiency even for p-terphenyl and diphenylacetylene having fluorescence decay times of 0.95 ns and 8 ps, respectively. The exciplex emission band is sensitive to an external magnetic field and exerts a very large observed magnetic field effect of up to 20%, the maximum possible value under the conditions of the described experiment.
authors.affiliation: Institute of Chemical Kinetics and Combustion SB RAS, 3, Institutskaya Str., 630090 Novosibirsk, Russian Federation. stass@ns.kinetics.nsc.ru.
authors.forename: Anatoly R
authors.initials: AR
authors.lastname: Melnikov
authors.forename: Evgeny V
authors.initials: EV
authors.lastname: Kalneus
authors.forename: Valeri V
authors.initials: VV
authors.lastname: Korolev
authors.forename: Igor G
authors.initials: IG
authors.lastname: Dranov
authors.forename: Alexander I
authors.initials: AI
authors.lastname: Kruppa
authors.forename: Dmitri V
authors.initials: DV
authors.lastname: Stass
mesh_terms: D000473:Alkanes / Q000737:chemistry* / Q000528:radiation effects*; D000814:Aniline Compounds / Q000737:chemistry / Q000528:radiation effects; D005453:Fluorescence; D005609:Free Radicals / Q000737:chemistry / Q000528:radiation effects; D049449:Luminescence; D060526:Magnetic Fields; D015394:Molecular Structure; D009281:Naphthalenes / Q000737:chemistry / Q000528:radiation effects; D055668:Photochemical Processes; D012996:Solutions; D013052:Spectrometry, X-Ray Emission; D014965:X-Rays
chemical_list: D000473:Alkanes; D000814:Aniline Compounds; D005609:Free Radicals; D009281:Naphthalenes; D012996:Solutions; C007548:n-dodecane; C031721:naphthalene; C015157:N,N-dimethylaniline