Photolysis of alkaline-earth nitrates

Peroxynitrite and nitrite ions are the diamagnetic products of photolysis (with light at a wavelength of 253.7 nm) of alkaline-earth nitrates; the paramagnetic products and hydrogen peroxide were not found. The structural water in alkaline-earth nitrate crystals did not affect the qualitative composition of the photodecomposition products. The quantum yield of nitrite ions was 0.0012, 0.0038, 0.0078, and 0.0091 quanta^?1 and that of peroxynitrite ions was 0.0070, 0.0107, 0.0286, and 0.0407 quanta^?1 for Sr(NO₃)₂, Ba(NO₃)₂, Ca(NO₃)₂ · 4H₂O, and Mg(NO₃)₂ · 6H₂O, respectively.     

Schmidt modes and entanglement

Motivated by their frequent use in quantum mechanical studies of entanglement, we give a brief overview of Schmidt modes and Schmidt decompositions of two-particle wave functions. We discuss methods of their derivation and include a little-known approach used in the original work by E. Schmidt [Math. Annalen, 63 (1906), 433]. This employs the bipartite wave function itself rather than the more complicated two-party reduced density matrix. As an illustration, Schmidt modes for two-photon polarisation qutrits are derived in a general form. The derivation is accompanied by a series of simple examples with special choices of parameters. Relationships between Schmidt modes, polarisation Stokes vectors and entanglement are also discussed.     

Hole Localization in Thallium Nitrate (I)

Russian Physics Journal - Using the EPR method, an identification of paramagnetic centers formed in TlNO3 under γ-irradiation at 77 and 300 K is performed. Their spectral characteristics,...     

Drift study of the products formed by radiolysis and photolysis of alkaline nitrates

The products of the radiolysis and photolysis of crystalline sodium, potassium, rubidium, cesium nitrates have been investigated by the diffuse reflectance infrared Fourier transform spectroscopy. The bands in the 1260-1220 and 804-809 cm^?1 regions observed after the n -irradiation and photolysis by a light with the wave length 253.7 nm of crystalline alkali nitrates were identified as the vibrational modes of NO^? ₂ x ₃ and x ₂, respectively. The frequency of the x ₃ oscillation of nitrite ions decreases from 1260 cm^?1 up to 1220 cm^?1 with the increase of the atomic weight or polarizability of a cation. The detection limit of the nitrite ions (1 ‐ 10^?7 mol g^?1) for the diffuse reflection method has been determined. The bands observed in KNO₃, RbNO₃ and CsNO₃ spectra in the 947-940 and 722-737 cm^?1 regions appearing only after photolysis are due to stretch oscillations of the peroxide bond O-O and wagging oscillations of the -ON=O group of peroxynitrite accordingly.     

Effect of Ammonium Ions on the Radiation Degradation of Potassium Nitrate

The formation and thermal conversion of paramagnetic centers in -irradiated single crystals of potassium nitrate with an ammonium nitrate impurity was studied by EPR spectroscopy. It was found that the presence of ammonium nitrate decreased the radiation-chemical yield of nitrite ions, which are one of the final radiolysis products of nitrate-containing compounds. An analysis of the results of a study on NO₂ orientation in the KNO₃ crystal lattice with an impurity of NH⁺ ₄ allowed us to propose a mechanism for selective N–O bond rupture in the radiation-stimulated dissociation of the nitrate ion in a potassium nitrate matrix.     

Efficiency of the formation of peroxonitrite during the photolysis of potassium nitrate doped with thallium ions

It is established that the introduction of thallium(I) ions into the potassium nitrate lattice decreases the quantum yield of peroxonitrite during the photolysis of this substance at a wavelength of 253.7 nm because of a lower efficiency of peroxonitrite formation from nitrate ions in the triplet excited state with symmetry E′ as compared to their singlet state of the same symmetry. It is suggested that the primary stage of the formation of peroxonitrite in the crystal is the dissociation of the excited nitrate ion with symmetry E′, a process accompanied by the formation of the [NO^?...O₂] complex.     

Transformations of radicals and ions in irradiated sodium sulfate doped with nitrate ions

The structure and properties of the paramagnetic centers formed by γ-irradiation at 77 K in sodium sulfate doped with nitrate ions have been investigated by the EPR method. The NO^2? ₃, NO₂ and SO^? ₄ radicals have been identified. The orientation of NO^2? ₃ relation to crystallographic axes is determined. In the 77-400 K temperature range the transformations of observable radicals have been studied. The mechanisms of their formation and thermal annealing have been discussed. The symmetry of nitrate ions in sodium sulfate was investigated by diffuse reflectance infrared Fourier transform spectroscopy. At the concentration of NO^? ₃ up to 5.5 × 10¹⁸ g^?1 the nitrate ion was supposed to have a planar or pyramidal configuration of the D_3h or C_3V symmetries. At the concentration of the dopant higher than 5.5 × 10¹⁸ g^?1 the nitrate ions with the C_2V symmetry were observed.