Search results for "iTED"

Luminescence and scintillation properties of Mg-codoped LuAG:Pr single crystals annealed in air

2017

Abstract The influence of the Mg 2+ codoping and annealing in the air on the scintillation and luminescence characteristics of Pr-doped lutetium-aluminum garnet crystals (LuAG) was studied to find a possible positive effect of Pr 4+ . The overall scintillation efficiency under X-ray excitation of the annealed Pr- doped samples decreased with increasing Mg concentration. This was explained by increased overlap of the Pr 3+ 5d-4f emission with the charge-transfer (CT) absorption band of the Pr 4+ ion stabilized by Mg 2+ . This absorption caused even greater decrease of the light yield, as the light is collected from the whole sample volume in the pulse-height spectrum measurement. Electron ce…

Luminescence and Light‐Driven Energy and Electron Transfer from an Exceptionally Long‐Lived Excited State of a Non‐Innocent Chromium(III) Complex

2019

Abstract Photoactive metal complexes employing Earth‐abundant metal ions are a key to sustainable photophysical and photochemical applications. We exploit the effects of an inversion center and ligand non‐innocence to tune the luminescence and photochemistry of the excited state of the [CrN6] chromophore [Cr(tpe)2]3+ with close to octahedral symmetry (tpe=1,1,1‐tris(pyrid‐2‐yl)ethane). [Cr(tpe)2]3+ exhibits the longest luminescence lifetime (τ=4500 μs) reported up to date for a molecular polypyridyl chromium(III) complex together with a very high luminescence quantum yield of Φ=8.2 % at room temperature in fluid solution. Furthermore, the tpe ligands in [Cr(tpe)2]3+ are redox non‐innocent, …

The Lyapunov dimension formula for the global attractor of the Lorenz system

2015

The exact Lyapunov dimension formula for the Lorenz system has been analytically obtained first due to G.A.Leonov in 2002 under certain restrictions on parameters, permitting classical values. He used the construction technique of special Lyapunov-type functions developed by him in 1991 year. Later it was shown that the consideration of larger class of Lyapunov-type functions permits proving the validity of this formula for all parameters of the system such that all the equilibria of the system are hyperbolically unstable. In the present work it is proved the validity of the formula for Lyapunov dimension for a wider variety of parameters values, which include all parameters satisfying the …

New analysis of ηπ tensor resonances measured at the COMPASS experiment

2018

We present a new amplitude analysis of the $\eta\pi$ $D$-wave in $\pi^- p\to \eta\pi^- p$ measured by COMPASS. Employing an analytical model based on the principles of the relativistic $S$-matrix, we find two resonances that can be identified with the $a_2(1320)$ and the excited $a_2^\prime(1700)$, and perform a comprehensive analysis of their pole positions. For the mass and width of the $a_2$ we find $M=(1307 \pm 1 \pm 6)$~MeV and $\Gamma=(112 \pm 1 \pm 8)$~MeV, and for the excited state $a_2^\prime$ we obtain $M=(1720 \pm 10 \pm 60)$~MeV and $\Gamma=(280\pm 10 \pm 70)$~MeV, respectively.

Molecular structures of Se(SCH3)2 and Te(SCH3)2 using gas-phase electron diffraction and ab initio and DFT geometry optimisations

2005

The molecular structures of Se(SCH3)2 and Te(SCH3)2 were investigated using gas-phase electron diffraction (GED) and ab initio and DFT geometry optimisations. While parameters involving H atoms were refined using flexible restraints according to the SARACEN method, parameters that depended only on heavy atoms could be refined without restraints. The GED-determined geometric parameters (rh1) are: rSe-S 219.1(1), rS-C 183.2(1), rC-H 109.6(4) pm; S-Se-S 102.9(3), Se-S-C 100.6(2), S-C-H (mean) 107.4(5), S-Se-S-C 87.9(20), Se-S-C-H 178.8(19)° for Se(SCH3)2, and rTe-S 238.1(2), rS-C 184.1(3), rC-H 110.0(6) pm; S-Te-S 98.9(6), Te-S-C 99.7(4), S-C-H (mean) 109.2(9), S-Te-S-C 73.0(48), Te-S-C-H 180.…

Triplet 12B-12C-12N : Search for States with Halo

2020

Previously in [1] neutron halo was confirmed for the 2¯, 1.67 MeV and 1¯, 2.62 MeV states in 12B on base of Asymptotic Normalization Coefficients (ANC) method analysis of the obtained experimental data. An unexpected result was received for the unbound 3¯, 3.39 MeV state. Its halo radius was found to be increased and equal to ~5.9 fm. This result can be considered as an evidence of the halo-like structure in this 12B state. It should be noted that last neutron in this state has a non-zero orbital momentum (l = 2). So question arises about possible existence of states with halo in other members of the isobaric triplet 12B–12C–12N. We can expect the formation of a proton halo in the 2¯, 1.19 …

Inverted energy gap law for the nonradiative decay in fluorescent floppy molecules: larger fluorescence quantum yields for smaller energy gaps

2019

A data survey on experimental fluorescence quantum yields of (multi)substituted dicyano-distyrylbenzenes in fluid solution evidences that non-radiative decay increases with the Franck-Condon energy (E-FC), being opposite to the conventional energy gap law. Quantum-chemistry indicates that this is controlled by access to the conical intersection (CI) following the Bell-Evans-Polanyi principle as a first-step approximation for this family of molecules; the variations in E-FC among the different compounds are found to be decisive, while those of E-CI are estimated to be weaker or even enhancing the effect. The current findings may have significant consequences for the design of molecules for o…

The Politics of Explanatory Nationalism and the Evolution of the United Nations Agenda on Multinational Enterprises

2020

The contemporary world continues to suffer from a number of social problems that are global in scope but impact the Global South disproportionately. While broad and coordinated policy responses to overcome these problems exist, such policies are not shaped solely by the political will to address the problems. On the contrary, their content largely depends on how societies in general and the social problems in particular are routinely explained and conceptualized. We refer to these as explanatory tendencies or paradigms of explanation. As complex problems always have multiple root causes with long causal chains, explanations of these causes necessarily involve some assumptions about relevant…

2016

AbstractUnderstanding the dynamics of zoonotic pathogens in their reservoir host populations is a prerequisite for predicting and preventing human disease epidemics. The human infection risk of Puumala hantavirus (PUUV) is highest in northern Europe, where populations of the rodent host (bank vole, Myodes glareolus) undergo cyclic fluctuations. We conducted a 7-year capture-mark-recapture study to monitor seasonal and multiannual patterns of the PUUV infection rate in bank vole populations exhibiting a 3-year density cycle. Infected bank voles were most abundant in mid-winter months during years of increasing or peak host density. Prevalence of PUUV infection in bank voles exhibited a regul…

A novel 2,6-bis(benzoxazolyl)phenol macrocyclic chemosensor with enhanced fluorophore properties by photoinduced intramolecular proton transfer

2023

Macrocyclic ligand L, in which a 2,6-bis(2-benzoxazolyl)phenol (bis-HBO) group is incorporated in triethylenetetramine, was designed and synthesized with the aim of creating a chemosensor with high selectivity and specificity for metal cations in an aqueous environment. The availability of several proton acceptors and donors, and amine and phenol hydroxy groups, respectively, affects the keto-enol equilibrium in both the ground and excited states, and the ligand properties show dependence on the pH of the solution. L is fluorescent in the visible range, through an excited-state intramolecular proton transfer (ESIPT) mechanism. The results of an exhaustive characterization of L by spectrosco…