Current induced deformation of charge density waves in orthorhombic TaS3

The low electric field ohmic resistance R of orthorhombic TaS₃ measured at 90 and 120 K well below the Peierls transition temperature depends on the product of a temperature difference ΔT applied along the sample and the sign of a previously applied current pulse if this pulse is larger than threshold for non-ohmic conductivity. This resistance change is about ΔR/RΔT ∽ 1×10^-3 K^-1 for a pure sample and ΔR/RΔT ∽ 6×10^-3 K^-1 for a slightly electron irradiated one at 90 K. The relative resistance change is insensitive to the sample length. We deduce that the CDW current changes inhomogeneously the Peierls gap E_g. ΔE_g < O at the contact where the CDW current enters and ΔE_g > O at the exit. The effect is attributed to a CDW current induced inhomogeneous deformation of the CDW itself.     

Temperature dependence of the energy separation between Γ and L minima in n-type GaSb

Energy separation ΔE_c between Λ and L minima of GaSb conduction band is deduced from temperature dependence of tunneling current in p−n junctions. ΔE_c is found to inceasing vx. temperature with a coefficient d(ΔE_c/dT) of about - 2.10^-4eV/dgK.     

Gravitational radiation from a particle with zero orbital angular momentum plunging into a Kerr black hole

We have computed the energy ΔE, the momentum ΔP and the angular momentum ΔJ of gravitational radiation induced by a particle of mass μ and of zero orbital angular momentum plunging in the θ = π/2 plane into a Kerr black hole of mass M(?μ) and angular momentum Ma. It is found that ΔE for a = 0.99M is 4.45 × 10^-2 (μ²/M)c², which is 4.27 times larger than that for the a = 0 case.     

Hyperfine structure of the <Emphasis Type="Italic">S</Emphasis> levels of the muonic helium ion

Corrections of the α⁵ and α⁶ orders to the energy spectrum of the hyperfine splitting of the 1S and 2S levels of the muonic helium ion are calculated with the inclusion of the electron vacuum polarization effects, nuclear-structure corrections, and recoil effects. The values ΔE ^hfs(1S) = ?1334.56 meV and ΔE ^hfs(2S) = ?166.62 meV obtained for hyperfine splitting values can be considered as reliable estimates for comparison with experimental data. The hyperfine structure interval Δ₁₂ = 8ΔE ^hfs(2S) ? ΔE ^hfs(1S) = 1.64 meV can be used to verify QED predictions.     

Low energy photoelectron spectroscopy of solids. Aspects of experimental methodology concerning metals and insulators

Both He(I) and He(II) ultraviolet photoelectron spectra (UPS) for metals (Ag, Au) and thin solid films of organic (anthracene) and inorganic compounds (LiF, LiCl, LiBr, LiI, NaF, NACl, Li₂SO₄, NaOH) are presented. The results of measurements on two different spectrometers have shown that both the bias voltage, V_b, applied to the solid sample, and the angle of incidence, Ø, of the photon beam with the sample are crucial to the accurate determination of the work function (metals) and binding energies (insulators). The true binding energy of a band in the UPS with respect to the vacuum level, E_b^vac, is defined as the minimum value of (hv - ΔE), where ΔE is the energy difference between the threshold of the SEED, E_T, and the band maximum. ΔE is maximized at low values of ø and of V_b. The intensity of photoelectron emission (signal) increases with both ø (2–30°) and V_b (5–20 V). It is recommended that the variation of ΔE with both ø and V_b should be observed in any determination of E_B^vac.     

The current-induced effect on the Jahn-Teller distortion in the La0.5Ca0.5MnO3 manganite

The influence of dc current on the resistivity ρ and the Young's modulus E of La_0.5Ca_0.5MnO₃ compound has been investigated by means of an in situ measuring method. At low temperatures, both the resistivity ρ and the relative modulus ΔE increase with the current. A relaxation behavior of ρ to the higher resistive state is observed at a fixed temperature and a constant current. After storing the sample for a few days, ρ decreases with the current, accompanying a slight drop of ΔE at low temperatures. Current-induced effects on ρ and ΔE are interpreted according to the current-induced interwinning of Mn³⁺O₆ octahedral distortion modes between Q₂- and Q₃-types, which is suggested to contribute to the variation of the resistivity.     

Antiferromagnetic hall effect nonlinear in the electric current

A new galvanoantiferromagnetic effect is predicted—the Hall effect nonlinear in the electric current, i.e., a potential difference that is transverse to the current and is associated with the antisymmetric contribution to the resistivity tensor, which violates Ohm’s law, for example, of the form Δρij=?Δρji∝LE, where L is the antiferromagnetism vector and E is the electric field. The indicated contribution is characteristic for centrally antisymmetric antiferromagnets and can lead to a Hall field that is quadratic in the current: ΔE ^⊥ ∝ LJ ². Similarly, the effect ΔE ^⊥∝LJ ³ can exist in centrally symmetric antiferromagnets even in a state where the ordinary Hall effect, which is linear in J, is absent (for example, in hematite below the Morin point).     

Carbon segregation on a tungsten surface

New measurements are performed and a comprehensive analysis of experimental data is made on the dependence of equilibrium carbon coverage θ on a tungsten surface on its temperature and the degree of carbon loading. It is shown that if the volume is free of carbon, the variation of θ for T≥1400 K can be approximately described by the balance between the carbon flows through the boundary with the activation energy for transition into the bulk E₁=4.6 eV and the segregation energy ΔE=1.7 eV. For tungsten loaded preliminarily with carbon to a content of ≈10^?2 at. %, the θ(T) relation cannot be described in terms of the equilibrium conditions with constant E₁ and ΔE, because these quantities depend on the degree of carbon loading; E₁ grows from 4.6 to 6.8 eV and ΔE grows from 1.7 to 2.3 eV with an increase in carbon content from 0 to 10^?2 at. %. These variations are attributed to the bonds becoming stronger in carbon-loaded tungsten with increasing carbon content.     

Isobaric analogue states in28Si from (p, γ) reaction in27Al

Analogue states in²⁸Si are identified through (p, γ) reaction in²⁷Al in the energy rangeE _p =0.85–3.0 MeV. There appears hardly any indication of a mixing. Coulomb displacement energy ΔE _c for the isobaric pair²⁸Al-²⁸Si is obtained. A least squares analysis is also carried out on all the available experimental results of ΔE _c as a function of ¯Z/A ^1/3.     

Energy,momentum and angular momentum of gravitational radiation from a particle plunging into a non-rotating black hole

We have computed the energy ΔE, the momentum ΔP and the angular momentum ΔJ of gravitational radiation induced by a particle of mass μ and angular momentum μL_z plunging into a Schwarzschild black hole of mass M (?μ). It is found that the maximum value of ΔP is 4.5 × 10^?2 (μ/M) μc, ΔE/ΔJ ≈ 0.15c/(GM/c²), and a rotating ring plunging into a black hole emits less energy than a non-rotating one.     

Chemical shifts of the copper and cobalt K absorption discontinuities in some ternary compounds

The present paper reports the chemical shifts of the K X-ray absorption discontinuities of copper and cobalt in ternary compounds. Relationships between the chemical shifts ΔE of the discontinuities and the various bond parameters (C, E_g, and f_i) calculated from Levine's theory have been established. It is found that distinctly separate curves can be drawn for different valencies (Cu¹⁺ and Cu²⁺, Co²⁺ and Co³⁺) of the absorbing ions. Making use of Levine's method for calculating bond charges, the effective charges q on the absorbing ions have been evaluated. The dependence of ΔE on q has been confirmed.     

Correlation of x-ray chemical shift and bond parameters calculated from levine's theory

The Cu K absorption edge shift in the systems CuCl, CuBr, CuI, CuO, CuS, CuSe, Cu₂O, CuFeS₂ and CuCl₂ · 2H₂O has been studied using a Cauchois-type bent crystal X-ray spectrograph. The bond parameters ionic gap C^μ and average bond gap E^μ_gb calculated from Levine's theory have been correlated with the chemical shift ΔE. The correlation is found to be linear and further it has been observed that distinct separate curves between ΔE and the bond parameters C^μ and E^μ_gb can be drawn for Cu⁺¹ and Cu⁺² ions. The curves have been used to determine bond parameters for the system CuCl₂ · 2H₂O.     

On the separation of initial and final state effects in photoelectron spectroscopy using an extension of the auger-parameter concept

First, we show that the quantity Δβ(i) = ΔE_A(kii) + 2ΔE_B(i) — ΔE_B(k) is directly related to the final state relaxation contribution ΔE_R(i) of the binding energy shift ΔE_B(i). ΔE_A(kii) is the kinetic energy shift of the Auger transition which corresponds to the decay of a hole state with a hole in level k into a final state with two holes in level i. The shift parameter Δβ(i), which is based on information on two binding energies, is conceptually similar to Wagner's Auger parameter. To establish the relation between Δβ(i) and ΔR(i) one needs, however, less drastic approximations than in the case of Auger parameter shifts. The only approximation necessary is the assumption that ΔR(i) is determined by coulomb contributions.Secondly, we use Δβ (i) to analyse the experimental data of eighteen gaseous phosphorus-containing compounds obtained by Sodhi and Cavell¹. It is shown that ΔR(P_2p) is strongly related to changes in the polarizability of the ligands. The initial state effects derived from our study deviate from those expected on the basis of simple electronegativity considerations.     

Intermolecular potentials for ammonia based on the test particle model and the coupled pair functional method

The intermolecular interaction ΔE in (NH₃)₂ is investigated on the SCF level, with inclusion of correlation effects by means of the CPF method and within the simple test particle model. Whereas the linear hydrogen bonded structure is favoured on the SCF level, ΔE = -7·65 kJ mol^-1, the most stable geometry on the highest level of theory is a cyclic structure, ΔE = -12·96 kJ mol^-1. The minimum is very shallow and allows for appreciable angular motions. The test particle model reproduces the general features of ΔE but shows deviations in details. The computed potentials are used in MD simulations to compute static and dynamic properties of liquid NH₃. Good agreement with available experimental results is obtained throughout.     

Synthesis of p-hydroxycinnamic acid derivatives and investigation of fluorescence binding with bovine serum albumin

Four novel p-hydroxycinnamic acid amides, (E)-4-(3-oxo-3-((4-(N-(pyrimidin-2-yl)sulfamoyl)phenyl)amino)prop-1-en-1-yl)phenyl-acetate (SPPA), (E)-3-(4-hydroxyphenyl)–N-(4-(N-(pyrimidin-2-yl)sulfamoyl)phenyl)acrylamide (SPAA), (E)-4-(3-((4-(N-(4,6-dimethylpyrimidin-2-yl)sulfamoyl)phenyl)amino)-3-oxoprop-1-en-1-yl)phenyl acetate (SPOA), and (E)-N-(4-(N-(4,6-dimethylpyrimidin-2-yl)sulfamoyl)phenyl)-3-(4-hydroxyphenyl)acrylamide (SPHA), were synthesized. The chemical structures of these compounds were confirmed using ¹H-NMR, ESI-MS, and elemental analyses. SPPA and SPOA were determined using single-crystal X-ray diffraction analysis. The interactions of these four compounds with bovine serum albumin (BSA) were investigated through fluorescence and UV–vis spectral studies. The thermodynamic parameters (i.e., ΔH, ΔG, and ΔS) and the quenching constants were calculated. The binding constants and the number of binding sites, n, were investigated. The distances between BSA and its derivatives were obtained based on fluorescence resonance energy transfer, and the conformational changes in BSA were observed from synchronous fluorescence spectra.     

XPS-investigation of intramolecular charge transfer in polynitro-aminobenzenes

It has been shown that the shake-up energy ΔE¹, which depends on the ionization potential (IP) of the neutral (poly)nitro-aminobenzenes, vanishes for IP≈ 8.4 eV. The λ values, which measure the contribution of intramolecular charge-transfer configurations in the molecules-in-molecules models correlate rather well with the difference E_II- E₁, i.e., the difference of the peak positions corresponding to lower and higher binding energies.     

Viscosity and excess molar volume of binary mixtures of methanol with n-butylamine and di-n-butylamine at 303.15, 313.15 and 323.15 K. Characterization in terms of ERAS model

The excess molar volume V_m^E, viscosity deviation Δη, and excess Gibbs energy of activation ΔG^?E of viscous flow have been investigated from the density ρ and viscosity η measurements of binary mixtures of methanol with n-butylamine and di-n-butylamine over the entire range of mole fractions at 303.15, 313.15, and 323.15 K. The systems studied exhibit very strong cross association through strong O–H…N bonding between –OH and –NH– groups. As a consequence of this strong intermolecular association, both the systems have very large negative V_m^E and positive Δη and ΔG^?E over entire range of composition and at all the temperatures of investigation. V_m^E of the studied mixtures is consistently described by the ERAS model. The values of cross association constants K_AB illustrate that cross-associates are more pronounced in primary amine mixtures than that in secondary amine.     

Magnetopolaron states involving confined phonons in a semiconductor quantum well

Energy splitting ΔE _res in double magnetopolaron energy spectrum in rectangular quantum wells as functions of the well width d have been calculated. We have considered in the capacity of interaction leading to resonant coupling between electrons and phonons the interaction with confined phonons and (for comparison) with bulk LO phonons. We have obtained the conditions when the interaction with bulk phonons yields correct results. Calculations for AlAs/GaAs/AlAs and AlSb/InSb/AlSb structures have been performed. Alongside the parameter ΔE _res for a polaron, whose resonant magnetic field is determined by the condition Ω=ω _L1, where Ω is the cyclotron frequency and ω _L1 is the LO phonon frequency in the quantum well (A-polaron), we have calculated ΔE _res for D-(Ω=2ω _L1) and F-polarons (Ω=3ω _L1), which is a factor of $\sqrt 2 $ and $\sqrt 3 $ , respectively, smaller than ΔE _res for the A-polaron. Since the splitting ΔE _res for the A-polaron is very large (up to 0.2?ω _L1), it is more convenient to study in experiments D-and F-polarons since their resonant magnetic fields are lower. We have predicted existence of “weak” magnetopolarons, in which the splitting is proportional to a higher power of Frölich’s coupling constant α than α ^1/2.     

Fine and hyperfine structure of <Emphasis Type="Italic">P</Emphasis>-wave levels in muonic hydrogen

Corrections of order α ⁵ and α ⁶ are calculated for muonic hydrogen in the fine-structure interval ΔE ^fs = E(2P _3/2) − E(2P _1/2) and in the hyperfine structure of the 2P _1/2-and 2P _3/2-wave energy levels. The resulting values of ΔE ^fs = 8352.08 μeV, ΔẼ ^hfs(2P _1/2) = 7819.80 μeV, and ΔẼ ^hfs(2P _3/2) = 3248.03 μeV provide reliable guidelines in performing a comparison with relevant experimental data and in more precisely extracting the experimental value of the (2P–2S) Lamb shift in the muonic-hydrogen atom. Original Russian Text ? A.P. Martynenko, 2008, published in Yadernaya Fizika, 2008, Vol. 71, No. 1, pp. 126–136.     

Memory switching of germanium tellurium amorphous semiconductor

The dc conductivity and switching properties of amorphous GeTe thin film of thickness 262 nm are investigated in the temperature range 303-373 K. The activation energy ΔE_σ, the room temperature electrical conductivity σ_RT and the pre-exponential factor σ₀ were measured and validated for the tested sample. The conduction activation energy ΔE_σ is calculated. The I-V characteristic curves of the thin film samples showing a memory switching at the turnover point (TOP) from high resistance state (OFF state) to the negative differential resistance state (NDRS) (ON state). It is found that the mean values of the threshold electrical field E_th decreased exponentially with increasing temperatures in the investigated range. The switching activation energy ΔE_th is calculated. Measurements of the dissipated threshold power P_th and the threshold resistance R_th were carried out at TOP point at different temperatures of the samples. The activation energies ΔE_R and ΔE_P caused by resistance and power respectively are deduced. The results obtained support thermal model for initiating switching process in this system.