Exciton-induced lattice defect formation

The lattice defect formation in solid Ne induced by electronic excitation was studied using the selective vacuum ultraviolet spectroscopy method. The samples were excited with synchrotron radiation in the range of excitonic absorption n = 2Г(3/2). The dose dependence of the intensity distribution in the band of atomic type self-trapped exciton luminescence was analyzed. A direct evidence of the formation and accumulation of point lattice defects in solid Ne via the excitonic mechanism was obtained for the first time. The model of the permanent lattice defect formation is discussed

Kinetic study of inelastic radiation-induced processes in rare-gas cryocrystals

The processes of large-scale atomic displacements induced by exciton self-trapping were studied using the selective vacuum ultraviolet luminescence method. Models of Frenkel pairs creation in rare-gas crystals are discussed with a focus on excited-state mechanisms of defect formation. A simple kinetic model of defect accumulation in rare-gas samples is proposed

Exciton self-trapping into diatomic and triatomic molecular complexes in xenon cryocrystals

The recent study of molecular trapped centers in Xe cryocrystals was extended on triatomic self-trapped excitons. Time- and spectrally-resolved molecular luminescence was measured in the temperature range 5–60 K. The processes of intrinsic exciton self-rapping into diatomic and triatomic molecular complexes and extrinsic exciton trapping at lattice imperfections were separated by selective photoexcitation of Xe cryocrystals by synchrotron radiation. The temperature dependencies of triplet lifetimes of molecular exciton subbands were measured for the first time

Photon excitation of the third molecular continuum in solid krypton

Luminescence study of the near-ultraviolet continuum in nominally pure solid krypton under selective excitation by synchrotron radiation is presented. Intrinsic nature of the emission has been established. Clear threshold behavior at the band gap energy reveals the key role of the electron-hole pairs in a population of the continuum forming states

[1,2,5]Oxadiazolo[3,4-d]pyridazine 1,5,6-trioxides: efficient synthesis via the reaction of 3,4-bis(hydroxyimino)methyl)-1,2,5-oxadiazole 2-oxides with a mixture of concentrated nitric and trifluoroacetic acids and structural characterization

An efficient synthesis of [1,2,5]oxadiazolo[3,4-d]pyridazine 1,5,6-trioxides (1) from 3,4-bis(hydroxyimino)methyl)-1,2,5-oxadiazole 2-oxides using a mixture of concentrated nitric and trifluoroacetic acids has been developed. The scope of the unconventional reaction was established. The 4,7-dinitro[1,2,5]oxadiazolo[3,4-d]pyridazine 1,5,6-trioxide 1f represents a new high energy compound, unfortunately with low thermal stability. The parent [1,2,5]oxadiazolo[3,4-d]pyridazine 1,5,6-trioxide 1c was studied by single-crystal X-ray diffraction analysis which revealed a planar molecule with an unusually long intracyclic N–N bond of 1.668(5) Å and unexpected exo-cyclic bond angles at the nitroxyl nitrogen atoms. In the crystal, the molecules of 1c are bound to each other by strong π-π stacking and C–H⋯O hydrogen bonding interactions into a three-dimensional framework that results in a high crystal density of 1.833 gcm−3. © 201

[1,2,5]Oxadiazolo[3,4-d]pyridazine 1,5,6-trioxides: efficient synthesis via the reaction of 3,4-bis(hydroxyimino)methyl)-1,2,5-oxadiazole 2-oxides with a mixture of concentrated nitric and trifluoroacetic acids and structural characterization

An efficient synthesis of [1,2,5]oxadiazolo[3,4-d]pyridazine 1,5,6-trioxides (1) from 3,4-bis(hydroxyimino)methyl)-1,2,5-oxadiazole 2-oxides using a mixture of concentrated nitric and trifluoroacetic acids has been developed. The scope of the unconventional reaction was established. The 4,7-dinitro[1,2,5]oxadiazolo[3,4-d]pyridazine 1,5,6-trioxide 1f represents a new high energy compound, unfortunately with low thermal stability. The parent [1,2,5]oxadiazolo[3,4-d]pyridazine 1,5,6-trioxide 1c was studied by single-crystal X-ray diffraction analysis which revealed a planar molecule with an unusually long intracyclic N–N bond of 1.668(5) Å and unexpected exo-cyclic bond angles at the nitroxyl nitrogen atoms. In the crystal, the molecules of 1c are bound to each other by strong π-π stacking and C–H⋯O hydrogen bonding interactions into a three-dimensional framework that results in a high crystal density of 1.833 gcm−3. © 201