Electronic polarizabilities and sizes of ions in AN B10−N type semiconductors

Electronic polarizabilities and sizes of ions in A^N B^10?N type semiconductors (PbS, PbSe, PbTe and SnTe) have been deduced in the present study. The free ion polarizabilities of Sn²⁺ and Pb²⁺ ions are estimated approximately following the procedure of Pauling. The effect of crystalline potential is then estimated on free cation polarizabilities. An empirical relation between ionic radii and polarizabilities has been applied to deduce the ionic sizes and anion polarizabilities. The calculated molecular electronic polarizabilities agree well with the experimental values. The variation of dielectric constant with strain has also been estimated in each crystal and the results are explained in terms of the optical anisotropy parameter.     

Many-body theory for multipole polarizabilities and dispersion forces in helium-helium interactions

Linked cluster many-body perturbation theory has been developed for the calculation of the dynamic quadrupole polarizabilities of the helium atom in its ground state. The polarizabilities have been used to calculate the London dispersion force constants for He-He interactions. The results for the polarizabilities and the van der Waals constants compare very well with other standard values.     

High precision calculation of multipolar dynamic polarizabilities and two- and three-body dispersion coefficients of atomic hydrogen

In this paper we investigate a variationally stable procedure for multipolar dynamic polarizabilities calculation as well as the two- and three-body van der Waals coefficients of the hydrogen atom. This approach provides precise, fast convergent values for real and imaginary frequency-dependent 2 ^L -pole dynamic polarizabilities. Highly accurate two- and three-body van der Waals dispersion coefficients are calculated from dynamic polarizabilities at imaginary photon frequencies. The present approach is also precise for higher interaction orders. The results are compared with previous calculations found in the literature.     

Compton scattering on the pion and radiative pion photoproduction from the proton

The contribution of the pion polarizabilities to radiative pion photoproduction has been investigated. It has been shown how an extrapolation of future experimental data on radiative pion photoproduction to the pion pole can give information on the polarizabilities of pion.     

Effect of the crystal potential on electronic polarizabilities of ions in alkaline earth chalcogenides

The electronic polarizabilities of ions in alkaline earth chalcogenides are estimated by taking account of the effect of the crystalline potential. The polarizabilities thus obtained are found to present a good agreement with experimental data. It has been shown that the polarizabilities and radii of alkaline earth and chalcogenide ions follow the polarizability-radius cube relation approximately well.     

Study of Electric Polarizabilities of Nucleon with a Constituent Quark Model and Pion Meson Cloud

In this work, a subtle role of the pion meson cloud effect on the electric polarizabilities of the proton and neutron is stressed. It is shown that the electric polarizabilities of the proton and neutron, and the difference between the electric polarizabilities of the proton and neutron can be explained by including the pion meson cloud explicitly. However, the magnitude of the estimated mean-square charge radius of the neutron is still far from the measurement.     

Molecular polarizabilities of some amino acids 1. Glycine and L-alanine

Atom-dipole interaction model has been used to calculate the molecular polarizabilities, refractive indices along the direction of principal polarizabilities of glycine and L-alanine and the molar optical rotation of L-alanine. The results of the calculation have been compared with experimentally observed data from Kerr effect and polarimetric measurements.     

Ab initio calculations for the absorption spectra and polarizabilities of small sulfur clusters

Absorption spectra for Sn clusters （n=2...8） are calculated using an adiabatic time-dependent density functional formalism within the local density approximation （LDA）. We compare the calculated spectra with those computed using a simple LDA approach. The time-dependent LDA （TDLDA） spectra display a significant blue shift with respect to the LDA spectra. The calculated spectra present a variety of features that can be used for comparison with future experimental investigations. We also obtain a significant threshold absorption, which can distinguish between different ground states of the sulfur clusters. In addition, the polarizabilities of the clusters are calculated by using the higherorder finite-difference pseudopotential density functional method in real space. We find that the polarizabilities of the clusters considered are higher than the value estimated from the ＇hard sphere＇ model using the bulk static dielectric constant. The computed polarizabilities per atom tend to decrease with increasing cluster size. The polarizabilities are closely related to the HOMO-LUMO gaps and the geometrical configurations.     

Correlation between electronic polarizabilities and ionic radii in alkali halides

An analysis of the electronic polarizabilities and sizes of ions in alkali halides has been carried out by considering a relationship according to which the electronic polarizability of an ion should vary as the n th power of its radius. The values of crystal radii, polarizabilities and the exponent “n”have been calculated using the free ion data reported by Pauling. The values of “n” are found to be nearly 3 in most of the crystals suggesting the validity of the polarizability radius cube relation. The polarizabilities and crystal radii calculated in the present study agree well with those estimated by earlier investigators.     

Dipole polarizabilities of plasma-embedded Ps and H ions

We have investigated the effect of weakly coupled hot plasmas on the dipole polarizabilities of positronium negative ion and hydrogen negative ion. The plasma effect is taken care of by employing a screened Coulomb (Yukawa) potential of Debye type, and highly correlated exponential wave functions are used. Dipole polarizabilities for various screening parameters are reported.     

Nucleon polarizabilities in real and virtual Compton scattering: Recent theoretical issues

We review recent developments in the theoretical investigation of the nucleon polarizabilities. We first report on the static polarizabilities as measured in real Compton scattering, comparing and interpreting the results from various theoretical approaches. In a second step, we extend the discussion to the generalized polarizabilities which can be accessed in virtual Compton scattering, showing how the information encoded in these quantities can provide a spatial interpretation of the induced polarization densities in the nucleon.     

Raman excitation of (+)‐(R)‐methyloxirane and its origin of optical activity via bond polarizabilities

We studied the bond polarizabilities of chiral (+)‐(R)‐methyloxirane from its Raman intensities. The bond polarizabilities provide much information concerning the electronic structure of its nonresonant Raman‐excited virtual state. At the initial moment of Raman excitation by the 514.5 nm laser, the tendency of the excited charges (mapped out by the bond polarizabilities) is to spread to the methine bond near the stereogenic center and its triangular oxirane skeleton. Thereby, the coupling of the electric dipole induced by the excited charges in the methine bond and the magnetic moment vibrationally induced by the electric current in the triangular oxirane skeleton as the molecule vibrates is shown to be the key factor leading to its significant Raman chirality. When the final stage of Raman relaxation is approached, the relative magnitudes of the bond polarizabilities are congruent to the bond electronic densities of the ground state, which are otherwise by the theoretical quantities via the quantum chemical calculation. During Raman relaxation, we found that the polarizabilities of the peripheral C H bonds relax faster than the rest, as indicated by their relaxation characteristic times. Copyright © 2010 John Wiley & Sons, Ltd.     

Measurement of the proton spin polarizabilities at MAMI

The spin polarizabilities of the nucleon are fundamental structure constants which describe the response of the nucleon spin to an incident polarized photon. The most model-independent way to measure the nucleon spin polarizabilities is the Compton scattering with polarization degrees of freedom. Three Compton scattering asymmetries on the proton were measured in the Δ(1232) region using a polarized incident photon beam and a polarized (or unpolarized) proton target at the Mainz Microtron (MAMI). These asymmetries are sensitive to values of the spin polarizabilities. Fits to asymmetry data were performed using a dispersion model calculation, and a separation of all four proton spin-polarizabilities in the multipole basis was achieved. The values of the proton spin polarizabilities are presented.     

Local approach to polarizabilities and trends in the Raman spectra of semiconductors

The Raman spectra of several II-VI and III–V compounds are well described with one parameter, namely the ratio of non-linear intra-ionic polarizabilities of the individual ions. This approach is justified by the open-shell electronic configuration of the compounds and is based on a simple overlap shell model which reproduces the phonons in many binary compounds. The relations to bond polarizabilities and the anomalous case of oxides are discussed.     

碱金属原子多极极化率的解析计算及其应用

通过考虑碱金属原子中的价电子在模型势中的运动, 给出了碱金属原子激发态(包括分立谱和连续谱)的波函数, 导出了碱金属原子的多极动态极化率的计算式中所涉及的矩阵元的解析表达式, 实现了碱金属原子多极动态极化率的解析计算. 作为应用, 利用范德瓦尔斯相互作用系数与动态极化率之间的积分关系, 计算了异核基态碱金属原子间的三体相互作用系数, 将计算结果与此前用稳定变分方法得到的结果进行了比较, 结果显示两者是一致的. 此工作为后续研究激发态碱金属原子间的相互作用奠定了基础.     

手性分子2, 3-丁二醇的旋光拉曼光谱研究

本文从拉曼峰和旋光拉曼峰出发,通过键极化率和微分键极化率分析研究(2R, 3R)-2, 3-丁二醇. 通过分子C₁和C₂两种点群的优化结构,获得不依赖于这两种结构的结果 和有关这个手性系统物理图像的丰富信息.对分子拉曼键极化率分析,得出在拉曼弛豫过程中, 电荷主要从外围流向骨架结构.对分子微分键极化率的分析,显示在不对称C原子和与其相联系的H原子 两侧化学键, C-O和C-CH₃的微分键极化率的符号正好相反,意味着这个分子具有相当好的手性 不对称性质.对比对称和反对称的键极化率、微分键极化率,本文得到这样的结论: 对于(特别是键伸缩的)键极化率,(大体上是)对称的大于反对称的; 而对于微分键极化率则是反对称的大于对称的. 关键词： 旋光拉曼 键极化率 微分键极化率 2,3-丁二醇     

Atomic polarizabilities and shielding factors

A detailed discussion is given of the methods of calculating atomic polarizabilities and shielding factors and the relationships between them are demonstrated. The formulation of the uncoupled Hartree-Fock approximation is presented and it is shown that the methods are all approximate versions of it. A more accurate procedure, the coupled Hartree-Fock approximation, is described. Comprehensive tables of dipole and quadrupole polarizabilities and of quadrupole shielding factors are included together with an assessment of the probable accuracy.     

Electronic polarizabilities and sizes of ions in alkaline earth halides and alkali chalcogenides

An analysis of the electronic polarizabilities and sizes of ions in the crystals of alkaline earth halides and alkali chalcogenides has been performed using a relation between polarizability and ionic radius. The electronic polarizabilities and sizes of ions are calculated using the free state data reported by Pauling. The quantities obtained in the present study are found to vary from crystal and crystal, thus showing the deviations from the additivity rule. The results are discussed and compared with those obtained by other investigators.     

相互作用体系的极化率与拉曼光谱

分子的大多数光学性能取决于它的极化率和超极化率，例如折射率、旋光、Ｒａｙｌｅｉｇｈ和Ｒａｍａｎ散射、电光、磁光和非线性光学性能等［１］。分子间相互作用对于物质的性质有着深刻影响［２］，对于分子极化率及其有关的性能也是如此３］。本文在拉曼光谱强度理论（...     

Spin polarizabilities and characteristics of spin-1 hadrons related to parity nonconservation in the Duffin–Kemmer–Petiau formalism

Spin polarizabilities of spin-1 particles typical of spin-1/2 hadrons are established within the Duffin–Kemmer–Petiau formalism using the relativistically invariant effective tensor representation of Lagrangians of two-photon interaction with hadrons. New spin polarizabilities of spin-1 particles associated with the presence of tensor polarizabilities are also determined.