Scaling factors associated withM-furcations of the 1−μ∥x∥z map

A numerical study is made of the scaling behavior associated withM-furcations (M=3, 4, 5) in the mapx _t+1 =1–x _t ^z (z>1). The scaling constants and are calculated as functions ofz, as well as the more general scaling functions andf(a).     

On the gap problem for the sequence ∥mβ∥

We discuss the gap problem for the sequence m used in our previous Letter (D. H. Mayer, Lett. Math. Phys. 16, 139–143 (1988)).     

Quenching of ππ* triplet states of vaporous polycyclic aromatic compounds by oxygen

The oxygen quenching rate constants k _T ^O2 of the triplet state T ₁ of vapors of polycyclic aromatic hydrocarbons (PAHs) with strongly different oxidation potentials 0.44 eV < E _OX < 1.61 eV and energies of the triplet levels 14800 cm^?1 < E _T < 24500 cm^?1 (anthracene, 2-aminoanthracene, 9-nitroanthracene, chrysene, phenanthrene, fluoranthene, and carbazole) are estimated from the measured dependences of the decay rates and intensities of delayed fluorescence on the oxygen pressure P _O2. It is found that the rate constants k _T ^O2 vary from 4 × 10³ (9-nitroanthracene) to 4 × 10⁵ s^?1 Torr^?1 (2-aminoanthracene) and increase with decreasing oxidation potentials E _OX of PAHs. The rate constants k _T ^O2 for vapors and solutions are compared. The dependences of k _T ^O2 on the free energy of two intermolecular processes, namely, triplet energy transfer to oxygen and electron transfer, are analyzed. It is shown that the rate constants k _T ^O2 increase with decreasing electron transfer free energy, which proves that, along with energy transfer, charge-transfer interactions contribute to the quenching of the triplet states of PAH vapors.     

Graph-theoretical parameters for π-MO calculation of a series of aromatic amines in the light of DFT theory: comparison with experimental CT transition energies

Expressions for the energies of the highest occupied π-molecular orbitals of a series of aromatic amines have been derived in terms of the vertex weight h _N (for amine nitrogen) and edge weight k _C–N (for the C–N bond) by representing the amine molecule in terms of vertex- and edge-weighted graphs. Graph-theoretical methods have been used to evaluate the quantities involved in such expressions. The HOMO energies of the amines calculated by density functional theory using the 6-31++G** basis set have been correlated with these expressions to estimate the perturbational parameter h _N and the Coulomb integral α. The acceptability of the estimated values of α and h _N has been tested by their ability to explain the experimentally observed trends in the CT transition energies of a series of charge-transfer complexes of amines with tetracyanoethylene. An important structural feature, namely rotation of the –NH₂ group about the C–N bond due to steric repulsion with the nearest H-atom in the case of 1-amino compounds, has been observed by such a correlation. The result agrees well with the DFT-optimized geometries of the structures.     

In-situ formation and detailed analysis of imine bonds for the construction of conjugated aromatic monolayers on Au(111)

We present the synthesis of 4′-amino-4-mercaptobiphenyl (AMB) and its deposition from solution onto Au(111) substrates. The resulting organic thin films were characterized by contact angle, infrared reflection absorption spectroscopy (IRRAS), X-ray photoelectron spectroscopy (XPS), and near edge X-ray absorption fine structure (NEXAFS) measurements. It is demonstrated that the majority of AMB molecules are coupled to the gold surface via S–Au covalent bonds, although only little orientational order of the AMB layer could be detected by NEXAFS. Furthermore, aromatic imine bonds between AMB and 4-hydroxybenzaldehyde (HB), 4-carboxybenzaldehyde (CB), 4-methylbenzaldehyde (MB), or 4-(trifluoromethyl) benzaldehyde (TMB) have been successfully formed. As a result of the limited order, this coupling reaction was incomplete. Nevertheless, the experimental results confirmed the formation of conjugated aromatic imine bonds.     

Excited states and absorption spectra of β-diketonate complexes of boron difluoride with aromatic substituents

In the approximation of the time-dependent electron density functional theory, we have studied using the quantum-chemical method the nature of excited states of boron difluoride acetylacetonate F₂BAA and its substituted derivatives that contain aromatic groups with one or two benzene cycles in the β-position. Optimization of the geometry of complexes show coplanar positions of cycles for all compounds, except for that with the substituent C₆H₃(CH₃)₂. Based on the calculated transition energies and oscillator strengths, we have simulated the absorption spectra in the prevacuum range. The calculated absorption spectra have been compared with the experimental spectra in the gas phase or in solutions. We show that, in the absorption spectra of complexes that contain substituents with one benzene cycle, the first three bands are caused by the transition of π electrons of the substituent to the LUMO of the chelate cycle. In complexes with two cycles in the substituent, the number of these transitions increases to five. As the π system becomes more extended, a bathochromic shift of the first absorption band and an increase in the transition probability are observed.     

Fourier transform IR spectroscopic study of substituent effect in aromatic amino acids on the zwitterion–neutral molecule tautomeric equilibrium

Four aromatic amino acids (p-aminobenzoic, 4,6-diaminoisophthalic, o-aminobenzoic, and methylene-bis-anthranilic) were studied by FTIR spectroscopy. The first two molecules were found to exist in the solid phase exclusively in neutral form and the latter two in coexisting neutral and ionic forms. The shift of the tautomeric equilibrium from neutral molecule to zwitterion is determined by the character of substitution, molecular conformation, and the possibility of noncovalent bonds formed between the functional groups. The separation of charges becomes possible only if the conformers of the molecule include a structure with an OH….N intramolecular hydrogen bond. The proton is completely transferred from the acid group to the amino group when the strong intermolecular hydrogen bonds can stabilize the formed zwitterion. Otherwise, uncharged complexes with different degrees of proton transfer to the amino group are formed.     

Investigation of the Spectral Line Intensities of the ν9 Band of the Trans-Conformer of Ethylene

Russian Physics Journal - The intensities of 740 vibrational-rotational lines of the ν9 fundamental band in the IR spectrum of the trans-C2H2D2 molecule are first analyzed. The...     

On the interpretation of the results of the experimental test of the Askar’yan effect

The effect of the environment on the results of measuring the radio radiation spectrum is considered in the experimental simulation of the cascade shower by a high-energy γ-ray beam in a dense medium. The calculation shows that the character of the measured energy spectrum depends on the location of the receiving antenna with respect to the shower axis.     

A comparison of the reproducibility of the parameters of the ¹³C-aminopyrine breath test for the assessment of hepatic function

This study determined the within-subject and between-subject variability of different ways of expressing the results of the (13)C-aminopyrine breath test ((13)C-ABT) and the effect of shortening the test duration. The (13)C-ABT was conducted on three separate occasions in 10 healthy volunteers and on a single occasion in 22 patients with established liver cirrhosis. The within-subject variability of cumulative percentage dose recovered (cPDR), using measured CO(2) production rate (VCO(2)), in the reference group over three trials was 15% over 120 min. Higher within-subject variability in cPDR would have been evident if the test was terminated at either 30 or 60 min. Substitution of predicted VCO(2) to calculate cPDR yielded comparable values at all time points. Significant differences between cirrhotics and reference group were evident after just 10 min using PDR/h, cPDR or enrichment (all P<0.05). The ABT demonstrates clinically acceptable reproducibility. Shortening of the duration may make the test more acceptable clinically, but it is associated with increasing imprecision.     

Calculation of the phase diagram of the TiZr alloy and investigation of the tendency toward separation of the ω phase

The electronic, structural, and thermodynamic properties of the TiZr equiatomic alloy have been calculated in terms of the electron density functional theory and Debye-Grüneisen model. The calculated lattice parameters a and c/a agree well with experimental data for the α, ω, and β phases. It has been shown that the ω phase is stable at atmospheric pressure and low temperatures, and it remains energetically more favorable up to T = 600 K. In the temperature range 600 K < T < 900 K, the α phase becomes stable, and above 900 K, the β phase of the TiZr alloy is stable. The phase diagram constructed in this study agrees qualitatively with the available experimental data. A tendency toward separation of the TiZr equiatomic alloy in the ω phase has been analyzed. It has been demonstrated that, in the ground state, the TiZr equiatomic alloy in the ω phase exhibits a tendency toward ordering rather than toward phase separation.     

Description of the evolution of the state of “josephson atoms” in the context of the informational interpretation of quantum mechanics

The evolution of a quantum system is informationally interpreted and used to describe decay in the coherent states of Josephson atoms, including qubits based on two- and three-junction superconducting quantum interferometers. The reduced Lindblad equation is employed to examine the measurement procedure of the Josephson qubit state and the influence of a measuring device on its coherent-state decay.     

Aromaticity on the edge of chaos: an Ab initio CCSD(T) study of the bimodal balance between aromatic and non-aromatic structures for 10-π-diheterocins and heteronins

CCSD(T) coupled cluster ab initio SCF-MO calculations for 10-π-heteroannulenes reveal a range of potential surface characteristics, ranging from single-minimum aromatic planar species to triple-minimum systems involving both planar-aromatic and the two enantiomers of a C₂ symmetric non-planar non-aromatic species. For the specific case of 1,4-dioxocine, the existence of barriers separating the three minima is attributed to an anti-aromatic Möbius-like transition state connecting the two equilibrium forms.     

Evaluation of the Intensities of Spectral Lines under the Influence of Interferences and the Determination of Global Maxima of the Mass–Spectrum Peaks

We describe the technique by which the intensity of spectral lines can be evaluated and the global maxima of the mass–spectrum peaks under the influence of pulse interferences can be defined using an experimental setup based on a commercial MX–7304A mass spectrometer, IBM personal computer (PC), and a digital extremum regulator that allows one to ignore local extrema and bring about automatic search for a global maximum of the mass–spectrum peak and its tracking with an accuracy of 0.0012% at a speed of response of 50 kHz, elevated speeds of the scanning of masses 500 amu/sec, and stability of regulation.     

Analysis of the Structure of the Bands in the IR Spectrum of β-D Glucose by the Regularized Method of Deconvolution

Deconvolution of the IR absorption spectrum of -D glucose in the spectral range 1500–450 cm^–1 has been carried out. The results of the deconvolution were compared with the IR and Raman spectra recorded at room and low temperatures and with the data obtained by theoretical calculations for the frequencies of the normal vibrations of the -D glucose molecule in the crystalline state. It is shown that deconvolution of the IR spectra recorded at room temperature makes it possible to separate the bands observed experimentally only at a very low temperature of the sample and a number of components that were not resolved earlier. The number of bands separated on deconvolution of the IR spectra of -D glucose in the spectral range 1500–450 cm^–1 is more than twice the number of visible absorption maxima in the usual spectrum. The results of deconvolution of the IR spectrum of -D glucose are in good agreement with the data of theoretical calculations for the frequencies of the normal vibrations of the -D glucose molecule in the crystalline state. The existence of the factor-group (Davydov) splitting of a number of frequencies of the nondegenerate fundamental vibrations of molecules in a crystal cell has been revealed in the IR spectrum of -D glucose. It was concluded that the model of an isolated molecule is insufficient for detailed theoretical interpretation of the vibrational spectra of carbohydrates.     

Measurement of the integrated luminosity of the Phase 2 data of the Belle Ⅱ experiment

From April to July 2018,a data sample at the peak energy of the T(4 S) resonance was collected with the Belle Ⅱ detector at the SuperKEKB electron-positron collider.This is the first data sample of the Belle Ⅱ experiment.Using Bhabha and digamma events,we measure the integrated luminosity of the data sample to be(496.3±0.3±3.0) pb~(-1),where the first uncertainty is statistical and the second is systematic.This work provides a basis for future luminosity measurements at Belle Ⅱ.     

The Structure of the Algebra of Observables in the Intermediate Situation of the ∈-Model

We look at the action of the spin-1/2 operatorsof quantum mechanics on the state of an entity in aphysical way, and use this as a guideline to define theoperators of the intermediate situations of a general spin-1/2 measurement model called the-model. Then we test the possible linearity ofthe operators so constructed.     

Analysis of the Structure of Thin Films of Zn‐Porphyrins by the Kinetics of the Fluorescence Anisotropy

The structure of thin films of Zntetraoctylphenylporphyrin (ZnTOPP) obtained by the spinning method is investigated. The kinetics of the decay of the fluorescence anisotropy of the films is analyzed in the form of a sum of exponents and by simulating the orientation of ZnTOPP complexes on the substrate (quartz) surface with allowance for the processes of the electron excitation energy transfer. The ZnTOPP films have a lamellar structure where individual layers form ordered domains. Within a domain, linear nonintersecting stacks of molecules are formed. In each stack the planes of the molecules are collinear, oriented perpendicularly to the surface of the substrate base, and form an angle of 45° with the directing axis of a stack.