Luminescence of Ytterbium in Complexes with Cryptands Containing Bipyridine and Biisoquinoline Fragments

Some characteristics of 4fluminescence of an ytterbium ion with cryptands containing bipyridine and biisoquinoline fragments have been studied for the first time. The relationship has been established between the changes in these characteristics and the structure of a macrocyclic ligand in H₂O and D₂O at 295 and 77 K. It is shown that the highest intensities and lifetimes of 4fluminescence are observed in those complexes where a lanthanide ion is most effectively protected against water molecules.     

Near Infrared Luminescence of Lanthanides in Complexes with Organic Dyes

Spectral-luminescence characteristics of Yb³⁺ and Nd³⁺ ions in water solutions of their complexes with some organic dyes of sulfophenylphthalexones group have been considered. Complexes can be efficiently excited with visible light (_exc = 532 nm). 4f-Luminescence as a result of energy transfer from the dye moiety to the lanthanide ion was shown. Complexation of new polydentate ligand L of sulfophenylphthalexones type increases the luminescence lifetimes because of the reduced solvation of the ion by water. They were determined as 12.60 s for complex Yb-L and 1.45 s for Nd-L.     

Peripheral fragmentation of relativistic nuclei 11B in nuclear track emulsion

Data obtained from a nuclear track photoemulsion exposed to a beam of ¹¹B nuclei with a momentum of 2.75 GeV/c per nucleon are reported. Peripheral interactions where the total charge of particles emitted within the forward cone of relativistic fragmentation is equal to the charge of the projectile nucleus are analyzed to study the clustering of the ¹¹T nucleus. It is found that the three-body breakup of 2 + 2 + 1 charge configuration is a leading process. Tritons are revealed to play a crucial role in the most peripheral interactions of this type. Events interpreted as charge exchange of the 11B nucleus to excited states of the ¹¹C* nucleus above the nucleon-coupling threshold were observed for the first time. Prospects for studying the ¹¹C nucleus are discussed.     

Magnetic Ordering of Strongly Magnetized Massive Nd<Subscript>2</Subscript>Fe<Subscript>14</Subscript>B Magnets

The magnetic ordering of a strongly magnetized massive rectangular magnet is studied via magnetic force microscopy. The magnetic ordering structures on the magnet’s surface are determined. An attempt is made to interpret the observed magnetic ordering by analyzing the simplest magnetic ordering models theoretically.     

Fluorine spin–spin coupling constants of pentafluorobenzene revisited at the ab initio correlated levels

All possible spin–spin coupling constants, ¹⁹F–¹⁹F, ¹⁹F–¹³C, and ¹⁹F–¹H, of pentafluorobenzene were calculated at five different levels of theory, HF, DFT, SOPPA (CCSD), CCSD, and the SOPPA (CCSD)-based composite scheme with taking into account solvent, vibrational, relativistic, and correlation corrections. Most corrections were next to negligible for the long-range couplings but quite essential for the one-bond carbon–fluorine coupling constants. Hartree–Fock calculations were found to be entirely unreliable, while DFT results were comparable in accuracy with the data obtained using the wave function-based methods.     

Indirect relativistic bridge and substituent effects from the ‘heavy’ environment on the one‐bond and two‐bond 13C1H spin–spin coupling constants

Indirect relativistic bridge effect (IRBE) and indirect relativistic substituent effect (IRSE) induced by the ‘heavy’ environment of the IV‐th, V‐th and VI‐th main group elements on the one‐bond and geminal ¹³C? ¹H spin–spin coupling constants are observed, and spin‐orbit parts of these two effects were interpreted in terms of the third‐order Rayleigh–Schrödinger perturbation theory. Both effects, IRBE and IRSE, rapidly increase with the total atomic charge of the substituents at the coupled carbon. The accumulation of IRSE for geminal coupling constants is not linear with respect to the number of substituents in contrast to the one‐bond couplings where IRSE is an essentially additive quantity. Copyright © 2015 John Wiley & Sons, Ltd.     

On uniqueness of solution of a reverse problem of magnetic location

An analysis of solution uniqueness for a problem of magnetic dipole localization based on known values of magnetic field strength vectors at two points is presented. It is shown that a usage of two triples (pairs) of sensors is sufficient to solve a 3D (2D) problem of arbitrary magnetic dipole localization with a satisfactory number of crude errors.     

Luminescence of metal complexes of chelate-substituted tetraphenylporphyrin

The luminescence and absorption spectra of some metal complexes of new tetraphenylporphyrin derivatives containing a chelating group with a heavy atom in the ligand structure were studied and compared with the properties of the zinc complex of unsubstituted tetraphenylporphyrin. The quantum yields of fluorescence and phosphorescence of liquid and frozen solutions of these compounds were measured. The life-times of delayed emission have been estimated, and the nature of bands in the absorption and luminescence spectra of the complexes and their relation with the structure are discussed.     

Calculations of nonlinear response properties using the intermediate state representation and the algebraic-diagrammatic construction polarization propagator approach: two-photon absorption spectra

An earlier proposed approach to molecular response functions based on the intermediate state representation (ISR) of polarization propagator and algebraic-diagrammatic construction (ADC) approximations is for the first time employed for calculations of nonlinear response properties. The two-photon absorption (TPA) spectra are considered. The hierarchy of the first- and second-order ADC∕ISR computational schemes, ADC(1), ADC(2), ADC(2)-x, and ADC(3/2), is tested in applications to H(2)O, HF, and C(2)H(4) (ethylene). The calculated TPA spectra are compared with the results of coupled cluster (CC) models and time-dependent density-functional theory (TDDFT) calculations, using the results of the CC3 model as benchmarks. As a more realistic example, the TPA spectrum of C(8)H(10) (octatetraene) is calculated using the ADC(2)-x and ADC(2) methods. The results are compared with the results of TDDFT method and earlier calculations, as well as to the available experimental data. A prominent feature of octatetraene and other polyene molecules is the existence of low-lying excited states with increased double excitation character. We demonstrate that the two-photon absorption involving such states can be adequately studied using the ADC(2)-x scheme, explicitly accounting for interaction of doubly excited configurations. Observed peaks in the experimental TPA spectrum of octatetraene are assigned based on our calculations.