Search

Tourmaline (TM) has received extensive interest in the purification field due to its unique spontaneous polarization. In this paper, the effects of three sizes of purified TM samples on the air filters were studied. The electrode performance of TM samples was investigated using piezoelectric and pyro‐electric experiments. The results show an electrode from the 0.074 mm separated TM had the superior property. Three types of TM powders with the highest B2O3% content were adhered to the filter to evaluate the filtration performance. Elbaite 0.074 mm with 9.34 B2O3% content had the optimal filtration efficiency when the pressure drop increased slightly. The Rietveld method was used to refine the samples X‐Ray diffraction patterns to obtain the crystal structure. The electrostatic adsorption caused by the TM spontaneous polarization contributes to improving the filtration property of the filter materials. [ABSTRACT FROM AUTHOR]

One of the alternatives to the Standard Model (SM) of elementary particles is the supersymmetry theories; the electric dipole moment (EDM) of elementary particles can serve as an excellent tool to confirm the validity of one of these models. For example: in the case of a neutron, the EDM, compatible with the SM, is within a range of to e cm, whereas the supersymmetry theories predict the presence of an EDM of much larger value, at the level of – e cm. Experiments on the search for EDM have been carried out for more than 50 years; however, most of them are based on charge-neutral particles (neutron, atoms). The EDM of charged particles (proton, deuteron) can be measured in a storage ring with the use of the phenomenon of the beam polarization precession in an electromagnetic field. The storage ring has a number of advantages when used as a tool for EDM measurement; however, there are also a number of problems. This paper discusses the main approaches to solving these problems: the BNL, spin wheel, and frequency domain methods. [ABSTRACT FROM AUTHOR]

Decreasing of layer thickness causes the decrease of polarization until it disappears due to the existence of depolarization field. Therefore, the search for strong piezoelectric materials is highly desirable for multifunctional ultra-thin piezoelectric devices. Herein, we propose a common strategy for achieving strong piezoelectric materials through the electronic asymmetry induced by the intrinsically asymmetric atomic character of different chalcogen atoms. Accordingly, in the tetrahedral lattice structures, for example, M4X3Y3 (M = Pd/Ni, X/Y = S, Se or Te, X ≠ Y) monolayers are proved to display excellent out-of-plane piezoelectricity. Ni4Se3Te3 possesses the largest piezoelectric coefficient d33 of 61.57 pm/V, which is much larger than that of most 2D materials. Enhancing the electronic asymmetry further increases the out-of-plane piezoelectricity of Janus M4X3Y3 materials. Correspondingly, the out-of-plane piezoelectricity is positively correlated with the ratio of electronegativity difference (Red) and the electric dipole moment (P). This work provides alternative materials for energy harvesting nano-devices or self-energized wearable devices, and supplies a valuable guideline for predicting 2D materials with strong out-of-plane piezoelectricity. [ABSTRACT FROM AUTHOR]

In this paper, we summarize the theoretical development on the electric dipole moment (CEDM) of light nuclei. We first describe the nucleon level CP violation and its parametrization. We then present the results of calculations of the EDM of light nuclei in the ab initio approach and in the cluster model. The analysis of the effect of several models beyond standard model (CBSM) is presented together with the prospects for its discovery. The advantage of the EDM of light nuclei is focused in the point of view of the many-body physics. The evaluations of the nuclear EDM generated by the -term and by the CP phase of the Cabibbo-Kobayashi-Maskawa (CKM) matrix are also reviewed. [ABSTRACT FROM AUTHOR]

This paper deals with the investigation results of nanocomposite permittivity based on magnetite nanoparticles and a polymeric matrix in electromagnetic field. Dependencies of real and imaginary parts of nanocomposite permittivity on the frequency of the electromagnetic field and size and concentration of magnetite nanoparticles have been found, and the dependence of imaginary part of permittivity on the real one has been determined. The Cole–Cole type has the dependence of the imaginary part of permittivity on the real one at high frequencies of electromagnetic field (at small values of the real part of permittivity) and hyperbolic behavior at small frequencies of the electromagnetic field (at large values of the real part of permittivity). Refraction index, loss angle tangent, and penetration depth of the nanocomposite. [ABSTRACT FROM AUTHOR]

In the search for clues to the matter–antimatter puzzle, experiments with atoms or molecules play a particular role. These systems allow measurements with very high precision, as demonstrated by the unprecedented limits down to 10−30 e cm on electron EDM using molecular ions, and relative measurements at the level of 10−12 in spectroscopy of antihydrogen atoms. Building on these impressive measurements, new experimental directions offer potential for drastic improvements. We review here some of the new perspectives in those fields and their associated prospects for new physics searches. This article is part of the theme issue 'The particle-gravity frontier'. [ABSTRACT FROM AUTHOR]

Detecting a non-zero electric dipole moment in a particle would unambiguously signify physics beyond the Standard Model. A potential pathway towards this is the detection of a nuclear Schiff moment, the magnitude of which is enhanced by the presence of nuclear octupole deformation. However, due to the low production rate of isotopes featuring such 'pear-shaped' nuclei, capturing, detecting and manipulating them efficiently is a crucial prerequisite. Incorporating them into synthetic diamond optical crystals can produce defects with defined, molecule-like structures and isolated electronic states within the diamond band gap, increasing capture efficiency, enabling repeated probing of even a single atom and producing narrow optical linewidths. In this study, we used density functional theory to investigate the formation, structure and electronic properties of crystal defects in diamond containing 229Pa , a rare isotope that is predicted to have an exceptionally strong nuclear octupole deformation. In addition, we identified and studied stable lanthanide-containing defects with similar electronic structures as non-radioactive proxies to aid in experimental methods. Our findings hold promise for the existence of such defects and can contribute to the development of a quantum information processing-inspired toolbox of techniques for studying rare isotopes. This article is part of the Theo Murphy meeting issue 'Diamond for quantum applications'. [ABSTRACT FROM AUTHOR]

Atomic partial charges cannot be physically measured but they play a significant role in many chemical theories and theoretical models. Therefore, they are, evaluated from experimentally acquired properties or calculated by quantum chemistry computational methods. This study is focused on determining chemical accuracy of various theoretical methods of computing atomic partial charges based on quantum chemistry. Values of gas-phase atomic partial charges were acquired by Mulliken (MUL) population analysis, natural bond analysis (NBO), Merz-Singh-Kollman (MSK) scheme, and atomic polar tensor (APT) charges computed considering Density Functional Theory and ab initio Møller-Plesset up to the second order levels. Correlations between the calculated values were determined by principal component analysis (PCA) and further confirmed by linear regression. The best agreement between experimentally evaluated atomic partial charges and theoretical values was obtained with the MSK scheme. [ABSTRACT FROM AUTHOR]

The He–McKellar–Wilkens (HMW) effect in noncommutative space has been explored through two distinct methodologies. One approach treats the neutral particle, which harbors a permanent electric dipole moment, as an unstructured entity, while the other approach considers the neutral particle as a composite system consisting of a pair of oppositely charged particles. To preserve gauge symmetry, we apply the Seiberg–Witten map. Surprisingly, both of these approaches converge on the same result. They independently confirm that, up to the first order of the noncommutative parameter (NCP), no corrections are observed in the phase of the HMW effect. Remarkably, these two approaches, although founded on fundamentally different mechanisms, yield identical conclusions. [ABSTRACT FROM AUTHOR]

Time-reversal had always been assumed to be a symmetry of physics at the fundamental level. In this paper we will explore the violations of time-reversal symmetry at the fundamental level and the consequence on thermodynamic systems. First, we will argue from current physics that the universe dynamics is not time-reversal invariant. Second, we will argue that any thermodynamic system cannot be isolated completely from the universe. We then discuss how these two make the dynamics of thermodynamics systems very weakly irreversible at the classical and quantum level. Since time-reversal is no longer a symmetry of realistic systems, the problem of how macroscopic irreversibility arises from microscopic reversibility becomes irrelevant because there is no longer microscopic reversibility. At the classical level of a thermodynamic system, we show that the H theorem of Boltzmann is still valid even without microscopic reversibility. We do this by deriving a modified H theorem, which still shows entropy monotonically increasing. At the quantum level, we explicitly show the effect of CP violation, small irreversible changes on the internal states of the nuclear and atomic energy levels of thermodynamic systems. Thus, we remove Loschmidt's objection to Boltzmann's ideas. [ABSTRACT FROM AUTHOR]

The orbits of artificial satellites are very sensitive to a large number of disturbances, whose effects add to the main force exerted by Earth's gravitational field. The most important perturbations, caused by solar radiation pressure, the Moon and the Sun gravitational fields, have been extensively discussed in the literature, and must be taken into account in order to correct the orbital motion, to prevent collisions between satellites in close orbits. In this paper we consider an additional source of acceleration arising from an electric dipole moment induced by the high altitude Earth electric field in a metallic satellite of spherical shape. The order of magnitude of such effect is estimated to be in the range of 10m/s. It is emphasized that the electric dipole moment effect(EDME) is dependent on the satellite shape and geometry and proportional to $E_0 v/r^4$. The Earth electric field E is largely influenced by atmospheric electromagnetic phenomena, such as whistler waves and thunderstorms. [ABSTRACT FROM AUTHOR]

The potential energy curves of 23 states of AlN radical are calculated to accurately determine the first several lowest-lying singlet and triplet states. The calculations are done using the CASSCF method, which is followed by the valence internally contracted MRCI approach. The rotationless radiative lifetimes of the vibrational levels are approximately 10−7–10−8 s for the C3Π, D3Π, and E3Δ states, 101–10−4 s for the A3Σ− state, and 10−4–10−5 s for the B3Σ+ state. The origins of the vibronic bands and the radiative lifetimes agree well with the available experimental and other theoretical results. The Einstein coefficients of many vibronic emissions are large for the C3Π–X3Π, C3Π–A3Σ−, D3Π–X3Π, D3Π–A3Σ−, and E3Δ–X3Π transitions and therefore, these transitions are strong. The emissions of the E3Δ–D3Π system are so weak that it is difficult to measure them through spectroscopy. The spectral distribution of the vibronic emissions is evaluated for the transitions of 12 pairs of states. In terms of the radiative lifetimes and transition probabilities obtained here, several spectroscopic routines for observing these states via spectroscopy are proposed. This paper calculates the potential energy curves, spectroscopic parameters, transition dipole moments, and transition probabilities of the AlN radical. The rotationless radiative lifetimes of the vibrational levels are of the order of 10−7 to 10−8 s for the C3Π, D3Π, and E3Δ states, 10−4 to 10−5 s for the B3Σ+ state, and 101 to 10−4 s for the A3Σ− state. The lifetimes of the C3Π, D3Π, and E3Δ states are almost determined by the C3Π–X3Π, D3Π–X3Π, D3Π–A3Σ, and E3Δ–X3Π systems, respectively. Overall, the C3Π–X3Π, C3Π–A3Σ−, D3Π–X3Π, and E3Δ–X3Π transitions, followed by the D3Π–A3Σ− and D3Π–C3Π transitions; the emissions are weak for the A3Σ−–X3Π, D3Π–B3Σ+, and E3Δ–D3Π systems. Curves of the TDM versus internuclear separation of 5pairs of states of the AlN. Unlabelled Image • Lifetimes are of the order of 10−7–10−8 s for the C3Π, D3Π, and E3Δ states. • C3Π–X3Π, C3Π–A3Σ−, D3Π–X3Π, D3Π–A3Σ−, and E3Δ–X3Π transitions are strong. • Lifetimes are 101–10−4 s for the A3Σ− state and 10−4–10−5 s for the B3Σ+ state. • Vibronic emissions of the E3Δ–D3Π system are weak. [ABSTRACT FROM AUTHOR]

This study calculates the potential energy curves of 12 Λ-S and 27 Ω states, which belong to the first dissociation channel of SiC + cation. The potential energy curves are computed with the complete active space self–consistent field method, which is followed by the valence internally multireference configuration interaction approach with the Davidson correction. The transition dipole moments are determined. Core-valence correlation and scalar relativistic correction, as well as extrapolation of the potential energies to the complete basis set limit are included. The spin-orbit coupling effect on the spectroscopic parameters and vibrational properties is evaluated. The vibrational band origins, Franck–Condon factors, and Einstein coefficients of spontaneous emissions are calculated. The rotationless radiative lifetimes of the vibrational levels are approximately 10 −5  s long for the e 2 Π state. The partial radiative lifetimes of vibrational levels are approximately 10 −7  s long for the 2 4 Π and 2 4 Σ − states, 10 −5 to 10 −6  s long for the 2 2 Σ − state and the first well of the 1 4 Π state, and very short for the second well of the 1 4 Π state. Overall, the emissions are strong for the 2 2 Σ − –c 2 Σ − , 2 4 Σ − –X 4 Σ − , 2 4 Π–X 4 Σ − transitions, and for the second well of the 1 4 Π–1 4 Σ + transition. The spectral range of emissions is determined. In terms of the radiative lifetimes and transition probabilities obtained in this paper, some guidelines for detecting these states are proposed via spectroscopy. These results can be used to measure the emissions from the SiC + cation, in particular, in interstellar clouds. [ABSTRACT FROM AUTHOR]

This study calculates the potential energy curves of 18 Λ-S and 50 Ω states, which arise from the C( 3 P g ) + P + ( 3 P g ) dissociation channel of the CP + cation. The calculations are made using the CASSCF method, followed by the icMRCI approach with the Davidson correction. Core-valence correlation and scalar relativistic corrections, as well as extrapolation to the complete basis set limit are included. The transition dipole moments are computed for 25 pairs of Λ-S states. The spin–orbit coupling effect on the spectroscopic and vibrational properties is evaluated. The Franck–Condon factors and Einstein coefficients of emissions are calculated. Radiative lifetimes are obtained for several vibrational levels of some states. The transitions are evaluated and spectroscopic measurement schemes for observing these Λ-S states are proposed. The potential energy curves, spectroscopic constants, vibrational levels, transition dipole moments, and transition probabilities reported in this paper can be considered to be very accurate and reliable. Because no experimental observations are currently available, the results obtained here can be used as guidelines for the detection of these states in appropriate spectroscopy experiments, in particular for observations in stellar atmospheres and in interstellar space. [ABSTRACT FROM AUTHOR]

A magnetic coil operated at cryogenic temperatures is used to produce spatial, relative field gradients below 6 ppm/cm, stable for several hours. The apparatus is a prototype of the magnetic components for a neutron electric dipole moment (nEDM) search, which will take place at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory using ultra-cold neutrons (UCN). That search requires a uniform magnetic field to mitigate systematic effects and obtain long polarization lifetimes for neutron spin precession measurements. This paper details upgrades to a previously described apparatus [1] , particularly the introduction of super-conducting magnetic shielding and the associated cryogenic apparatus. The magnetic gradients observed are sufficiently low for the nEDM search at SNS. [ABSTRACT FROM AUTHOR]

The potentials, spectroscopic properties and electric dipole moments of SrH+ are computed for 63 molecular states dissociating up to Sr2+ + H− using an ab initio approach. The ab initio formalism is based on large basis sets, nonempirical atomic pseudopotential for strontium core, correlation treatment for core valence through the effective core polarization potentials and for valence through full valence configuration interaction. Our theoretical molecular constants match published values very well and a large amount of new results is produced. Unusual potential shapes are found in 1Σ+ states often caused by avoided crossing series between them and imprinted by the ionic state Sr2+H−. The high potential energy curves suggest, it is possible to form H− or at least to neutralize H+ in collisions with strontium. © 2014 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Electroweak baryogenesis can be driven by the top quark in a general two Higgs doublet model with extra Yukawa couplings. Higgs quartics provide the first order phase transition, while extra top Yukawa coupling ρ t t can fuel the cosmic baryon asymmetry through the λ t Im ρ t t product, with flavor-changing ρ t c coupling as backup. The impressive ACME 2018 bound on the electron electric dipole moment calls for an extra electron coupling ρ e e for exquisite cancellation among dangerous diagrams, broadening the baryogenesis solution space. The mechanism suggests that extra Yukawa couplings echo the hierarchical structure of standard Yukawa couplings. Phenomenological consequences in the Higgs search and flavor physics are discussed, with μ and τ EDM touched upon. [ABSTRACT FROM AUTHOR]

Abstract: This paper reports deuteron vector and tensor beam polarization measurements taken to investigate the systematic variations due to geometric beam misalignments and high data rates. The experiments used the In-Beam Polarimeter at the KVI-Groningen and the EDDA detector at the Cooler Synchrotron COSY at Jülich. By measuring with very high statistical precision, the contributions that are second-order in the systematic errors become apparent. By calibrating the sensitivity of the polarimeter to such errors, it becomes possible to obtain information from the raw count rate values on the size of the errors and to use this information to correct the polarization measurements. During the experiment, it was possible to demonstrate that corrections were satisfactory at the level of 10−5 for deliberately large errors. This may facilitate the real time observation of vector polarization changes smaller than 10−6 in a search for an electric dipole moment using a storage ring. [Copyright &y& Elsevier]

In this paper we review research done by the recently founded Fribourg group for Atomic Physics (FRAP) using laser-assisted spin coherence spectroscopy of atomic samples in applied and fundamental physics. Spin coherence in optically pumped ensembles of paramagnetic atoms may be extremely long-lived when the samples are well shielded from external perturbations, like static or oscillating magnetic fields and field gradients, static electric fields, or crystalline field gradients. Conversely, such interactions may be studied with high sensitivity and precision when the decoherence that they produce is measured by optical means. We report on applications of this technique covering optical magnetometry for biomagnetic diagnostics, investigations of atomic impurities in quantum crystals, measurements of forbidden tensor polarizabilities and electric dipole moments, and the space-time resolved study of the diffusion of gas-phase atoms. [Copyright &y& Elsevier]

Based on fundamental symmetries, molecules cannot have a permanent electric dipole moment, although it is commonly used in the literature to explain the different molecular spectra for heteronuclear and homonuclear molecules. Electric-dipole rotational and vibrational spectra can indeed be observed in heteronuclear molecules, while they are missing in molecules with identical nuclei. This paper shows that the missing spectral features can be explained as an effect of the exchange symmetry for identical particles.

Van der Waals interactions between the valence electrons of the barium atom and the closed-shell cores have been studied using ab initio methods with a combination of pseudopotentials and core polarisation potential. We have reported the potential energy curves, the spectroscopic constants, the vibrational levels as well as the electric dipole moments for the ground and several excited states of Ba+Kr and BaKr complexes. Interesting behaviour has been observed in the potential energy curves, particularly for Σ+ states. This can show the strong repulsive interactions between Rydberg electrons and the Krypton atom. [ABSTRACT FROM AUTHOR]

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Adiabatic and diabatic studies are performed for the strontium hydride ion (SrH)+. Potential energy surface and electric dipole moment for the ground and all excited states dissociating up to the charge transfer ionic limit Sr2+H− have been investigated and analyzed in adiabatic and diabatic representations. The adiabatic approach uses the pseudo potential for the strontium atom complemented by core polarization potential operators, reducing the calculation to a two effective electrons system where full configuration interaction can be easily performed. The adiabatic results have been improved by a simple correction of the hydrogen electron affinity for all 1Σ+ states. The diabatic results reveal the strong imprint of the charge transfer ionic state in the 1Σ+ adiabatic states. [ABSTRACT FROM AUTHOR]

For adequate description of the adsorption and self-assembly of C60F18 polar molecules on the surface Au(111), quantum-chemical studies of the electronic and electrical properties of a single molecule are performed. Using various procedures of density functional theory, the electric dipole moment of the molecule, distributions of the electrostatic potential, electric-field magnitude and electron density are calculated with controlled accuracy for the first time. An improved value of the electric dipole moment of the C60F18 molecule is obtained in a range from 10 to 11 D. The known approximation of a point dipole for electric-field strength is shown to be fulfilled within an accuracy of 30% even at distances twice greater than the size of the molecule. The structural fragments of the calculated lowest unoccupied and highest occupied molecular orbitals are assigned to their images, which were previously obtained using scanning tunneling microscopy and spectroscopy. [ABSTRACT FROM AUTHOR]

Guided us by the scenario of weak scale naturalness and the possible existence of exotic resonances, we have explored in a Composite Higgs setup the interplay among three matter sectors: elementary, top partners and vector resonances. We parametrize it through explicit interactions of spin-1 -resonances, coupled to the -invariant fermionic currents and tensors presented in this work. Such invariants are built upon the Standard Model fermion sector as well as top partners sourced by the unbroken . The mass scales entailed by the top partner and vector resonance sectors will control the low energy effects emerging from our interplaying model. Its phenomenological impact and parameter spaces have been considered via flavor-dijet processes and electric dipole moments bounds. Finally, the strength of the Nambu-Goldstone symmetry breaking and the extra couplings implied by the top partner mass scales are measured in accordance with expected estimations. [ABSTRACT FROM AUTHOR]

The current work is dedicated to investigation of the interaction between self-assembled polar molecules of fullerene fluoride CF with the chemically active surface Ni(100) under radiation and heat treatments. X-ray photoelectron spectroscopy is used in combination with quantum-chemical simulation. For the first time, the transformation of an as-deposited dielectric continuous 2D thin film to a 3D island-type assembly with molecular ordering within the islands is shown to take place. The degree of coverage of the Ni surface by CF islands (0.6-0.7) and their height (~6 nm) are estimated. Quantum-chemical simulation shows that the chemisorption energy of the CF molecule on the Ni surface equals ~6.6 eV and fluorine atoms are located at a distance of 1.9 Å above the Ni surface. The results of the investigation provide an opportunity to create nanoscale ordered structures with local changes in the work function. [ABSTRACT FROM AUTHOR]

To provide an insight into the microscopic second and third-order nonlinear optical (NLO) behavior of chlorophyll a and crocin, we have computed the electric dipole moments ( μ), dispersion-free first hyperpolarizabilities ( β), frequency-dependent first and second ( γ) hyperpolarizabilities at 1064 nm wavelength area using time-dependent Hartree-Fock (TDHF) method. According to ab-initio calculation results, the examined compounds exhibit first and second hyperpolarizabilities with non-zero values, implying second and third-order NLO phenomena. [ABSTRACT FROM AUTHOR]

The structural and electronic properties of (SrLi)+molecular ion have been determined by the use ofab initioapproaches. Potential energy curves (PECs) with their spectroscopic constants (Re,De, ωe,Te,Beand ωeχe) have been calculated. Also, the vibrational properties and the electric dipole moments, either permanent (PDM) or transition (TDM) ones, have been investigated and analysed. Large Gaussian basis sets, the full valence configuration interaction (FCI) and the formalism of non-empirical pseudo-potential including the two approaches, effective core potential (ECP) and core polarisation potential (CPP), are analysed. Therefore, (SrLi)+is considered as a two effective electrons system. Numerous excited states of symmetries1,3Σ+,1,3Π and1,3Δ dissociating below the ionic limit Sr2+Li−have been investigated. This study shows interesting behaviours around the avoided crossing related to charge transfer involving important processes in physics and astrophysics such as dynamics, pre-dissociation and inelastic transitions. [ABSTRACT FROM AUTHOR]

The neutron, in addition to possibly having a permanent electric dipole moment as a consequence of violation of time-reversal invariance, develops an induced electric dipole moment in the presence of an external electric field. We present here a unified nonrelativistic description of these two phenomena, in which the dipole moment operator, D⃗, is not constrained to lie along the spin operator. Although the expectation value of D⃗ in the neutron is less than 10-13 of the neutron radius, rn, the expectation value of D⃗ 2 is of order r2 n. We determine the spin motion in external electric and magnetic fields, as used in past and future searches for a permanent dipole moment, and show that the neutron electric polarizability, although entering the neutron energy in an external electric field, does not affect the spin motion. In a simple nonrelativistic model we show that the expectation value of the permanent dipole is, to lowest order, proportional to the product of the time-reversal-violating coupling strength and the electric polarizability of the neutron. [ABSTRACT FROM AUTHOR]

We clarify the conditions or assumptions under which theoretical predictions of various models beyond the standard model give mainly in electric dipole moments. The correct interpretation of those conditions seems to be indispensable to the refinements of model building as well as to the mutual reliance in experimental and theoretical communities. The connections of these analyses to the recent experimental results at the LHC and the other places are also discussed. [ABSTRACT FROM AUTHOR]

This article describes the formation of homodimers from their constituting monomers, based on the rules set by a simple model of electric and hydrophobic interactions. These interactions are described in terms of the electric dipole moment ( D) and hydrophobic moment vectors ( H) of proteins. The distribution of angles formed by the two dipole moments of monomers constituting dimers were analysed, as well as the distribution of angles formed by the two hydrophobic moments. When these distributions were fitted to Gaussian curves, it was found that for biological dimers, the D vectors tend mostly to adopt a perpendicular arrangement with respect to each other, in which the constituting dipoles have the least interaction. A minor population tends towards an antiparallel arrangement implying maximum electric attraction. Also in biological dimers, the H vectors of most monomers tend to interact in such a way that the total hydrophobic moment of the dimer increases with respect to those of the monomers. This shows that hydrophobic moments have a tendency to align. In dimers originating in the crystallisation process, the distribution of angles formed by both hydrophobic and electric dipole moments appeared rather featureless, probably because of unspecific interactions in the crystallisation processes. The model does not describe direct interactions between H and D vectors although the distribution of angles formed by both vectors in dimers was analysed. It was found that in most cases these angles tended to be either small (both moments aligned parallel to each other) or large (antiparallel disposition). [ABSTRACT FROM AUTHOR]

This article presents results of measuring the neutron electric dipole moment (EDM) made by the Institut Laue-Langevin (ILL) reactor using the Petersburg Nuclear Physics Institute (PNPI) experimental installation. A double-chamber magnetic resonance spectrometer with prolonged holding of ultracold neutrons has been employed. The results determine the upper limit for EDM neutron quantity equal to | d| < 5.5 × 10 e cm at a 90% confidence level. [ABSTRACT FROM AUTHOR]

Several experimental and theoretical approaches can be used for a comprehensive understanding of solvent effects on the electronic structure of solutes. In this review, we revisit the influence of solvents on the electronic structure of the fluorescent probes Prodan and Laurdan, focusing on their electric dipole moments. These biologically used probes were synthesized to be sensitive to the environment polarity. However, their solvent-dependent electronic structures are still a matter of discussion in the literature. The absorption and emission spectra of Prodan and Laurdan in different solvents indicate that the two probes have very similar electronic structures in both the ground and excited states. Theoretical calculations confirm that their electronic ground states are very much alike. In this review, we discuss the electric dipole moments of the ground and excited states calculated using the widely applied Lippert-Mataga equation, using both spherical and spheroid prolate cavities for the solute. The dimensions of the cavity were found to be crucial for the calculated dipole moments. These values are compared to those obtained by quantum mechanics calculations, considering Prodan in vacuum, in a polarizable continuum solvent, and using a hybrid quantum mechanics-molecular mechanics methodology. Based on the theoretical approaches it is evident that the Prodan dipole moment can change even in the absence of solute-solvent-specific interactions, which is not taken into consideration with the experimental Lippert-Mataga method. Moreover, in water, for electric dipole moment calculations, it is fundamental to consider hydrogen-bonded molecules. [ABSTRACT FROM AUTHOR]

General classical equation of spin motion is explicitly derived for a particle with magnetic and electric dipole moments in electromagnetic fields. Equation describing the spin motion relative to the momentum direction in storage rings is also obtained. [ABSTRACT FROM AUTHOR]