Russian Ministry of the Emergency Situations

About: Russian Ministry of the Emergency Situations is a government organization based out in Moscow, Russia. It is known for research contribution in the topics: Combustion & Liquid crystal. The organization has 218 authors who have published 172 publications receiving 453 citations. The organization is also known as: Ministry of the Russian Federation for Civil Defence, Emergencies and Elimination of Consequences of Natural Disasters.

Technological Questions of Safe Elimination of CW Dumps on the Baltic Sea Bed

Abstract: During the forty-six years of the Cold War the natural purificatory abilities of the world’s oceans and land were mercilessly exploited.

Thermodynamics of Dissolution of Lead Oxide in NaOH-Na 2 CO 3 Melts

Abstract: The solubility of lead oxide in NaOH + (20%)Na2CO3 and NaOH + (40%)Na2CO3 melts was studied by the isothermal saturation method. The model mechanisms of dissolution were considered. The thermodynamic parameters were calculated.

Wide-line 1H NMR study of mesomorphic states of 4′-(octyloxy)-4-biphenylcarbonitrile

Abstract: A sample of 4′-(octyloxy)-4-cyanobiphenyl (8OCB) was studied in the temperature range −60–80°C by wide-line 1H NMR. The line shapes, half-widths, and second moments were determined. For the smectic phase of 8OCB, the relaxation times T1 and T2, the correlation time τc, and the degree of order were estimated. The 1H NMR spectral patterns and characteristics were found to be quite different for the crystalline, smectic, and nematic phases of 8OCB, which makes it possible to reliably identify the corresponding transitions and assess the molecular dynamics and molecular order of a structure. The temperature ranges, stability conditions, and other characteristics of the liquid crystalline phases that form on heating 8OCB were determined.

Calculation of the electronic structure and spectra for bacteriochlorophyll analogs

Abstract: Geometric structures and excited electronic states for free bases of bacteriochlorin (H2BC) and tetraazabacteriochlorin (H2TABC) as well as for their magnesium complexes (MgBC and MgTABC), analogs of bacteriopheophytin a (H2BPhea) and bacteriochlorophyll a (MgBPhea), have been calculated by a DFT method and by an INDO/Sm method (the INDO/S method with parameterization modified by the authors), respectively. The factors responsible for the observed bathochromic shift of the long-wavelength Q x (0–0) band of MgBPhea relative to H2BPhea, $ {{\updelta }}{E_{{Q_x}}} \cong - 300\;{\text{c}}{{\text{m}}^{ - 1}} $ , have been clarified. Contributions of one- and two-electron interactions to the resulting shift of the Q x (0–0) band have been analyzed in detail for the H2BC/MgBC, H2TABC/MgTABC, and porphine (H2P)/Mg porphine (MgP) pairs. It is shown that the bathochromic shift under consideration for the tetrahydro derivatives is caused by a decrease of the orbital energy gap e1–e−1 between the lowest unoccupied and highest occupied molecular orbitals. The variation of δ(e1–e−1) is large and amounts to –1660 and –920 cm–1 for the H2BC/MgBC and H2TABC/MgTABC pairs, respectively. The two-electron contributions, both into the energy of electronic configurations and due to the superposition of the configurations, produce a compensating hypsochromic effect such that the shifts $ {{\updelta }}{E_{{Q_x}}} $ are –260 and –150 cm–1 for the H2BC/MgBC and H2TABC/MgTABC pairs, respectively. It is also shown that the calculated electronic spectra for the considered molecules agree quantitatively with the experimental absorption spectra.

Luminescence and Geometric and Electronic Structures of Porphyrazines with Annelated 1,4-Diazepine Rings

Abstract: Absorption, fluorescence, and phosphorescence spectra of metal complexes of 4-tert-butylphenyl-substituted tetra(1,4-diazepino)porphyrazine MPADz4Ph8′ (M = Mg, Zn; PA = porphyrazine; Dz = diazepine; Ph = phenyl; Ph′ = 4-tert-butylphenyl) were recorded in DMF at 293 and 77 K. The Q(0–0) absorption bands of MgPADz4Ph8′ and ZnPADz4Ph8′ did not show signs of splitting, i.e., corresponded to the monomeric form. Singlet–triplet gaps of 4700 cm–1 for the Mg complex and 4800 cm–1 for the Zn complex were determined from fluorescence and phosphorescence spectra. Fluorescence quantum yields and lifetimes were measured. Rate constants of S1,2 → S0 radiative transitions and total rate constants of nonradiative deactivation of the S1,2 states were determined. Internal conversion rate constants were estimated. Conformer geometries of MgPADz4Ph8 (in the 6H tautomeric form) were calculated by density functional theory in the PBE/TZVP version. The conformer of symmetry S4v (D2d ) had the lowest energy. Nonplanar diazepine rings induced small but perceptible out-of-plane distortions in the central porphyrazine ring of MgPADz4Ph8. This feature correlated with the observed Stokes shifts of 400 and 350 cm–1 (at 293 K) for MgPADz4Ph8′ and ZnPADz4Ph8′ whereas the metal phthalocyanines had shifts of ~50 cm–1. Excited electronic states of MgPADz4Ph8 were calculated using INDO/Sm. The Q-state energy of 15,200 cm–1 agreed well with the observed value of 14,800 cm–1. Strong featureless absorption in the range 330–450 nm (Soret band analog) with maxima at ~25,000 and ~29,000 cm–1 was due mainly to two strong electronic transitions with calculated energies of 24,100 and 31,500 cm–1; a shoulder on the long-wavelength side of the Soret band at ~23,000 cm–1, to a transition of calculated energy 23,800 cm–1.