The stark effect in the 6snf Rydberg series of barium

The polarizabilities of the barium 6snf ³ F ₂ levels with principal quantum numbern ranging from 11 to 40 have been measured in a high resolution laser-atomic-beam experiment. In Coulomb approximation the contributions to the polarizabilities of all known even-parity levels connected with the³ F ₂ levels via the electric dipole operator have been calculated. In this way information on the to a large extent unknown 6sng ³ G ₃ Rydberg series is extracted. The results support earlier observations of a perturbation of this series in betweenn = 18 and 19, but no evidence has been found for a perturbation nearn = 14.     

Second and fourth order stark shifts in the 6snd 1 D 2 barium rydberg series

Stark splittings of⁶ snd ¹ D ₂ Rydberg states were measured betweenn=10 and 24 by quantum beat spectroscopy at very low electric field strengths, allowing the determination of tensor polarizabilities and atn=14, 19, and 24 the determination of tensor hyperpolarizabilities. The irregular behaviour of the tensor polarizabilities was explained by Coulomb approximation calculations. The fourth order contributions to the Stark Hamiltonian were written as effective operators. Representation in spherical tensor form gives tensors of rank zero, two, and four. The associated scalar and tensor hyperpolarizabilities were derived. Using these formulae, theoretical values for the hyperpolarizabilities were calculated.     

The Stark effect in the 6snf Rydberg series of barium

The Stark effect has been studied in the odd-parity 6snf^1,3F₃ Rydberg series of barium with high-resolution laser-atomic-beam spectroscopy. Scalar and tensor polarizabilities have been measured of 6snf¹F₃ levels with n=11–30 and of 6snf³F₃ levels withn = 12 ? 40. The contributions of the adjacent even-parity Rydberg levels to these polarizabilities have been calculated as far as data are available. This results in important additional information on the only partly known 6sng^1,3G₄ series and confirms the perturbation of these series atn = 24 by a 5d7dJ= 4 level. A tentative three-channel quantum-defect-theory analysis of the^1,3G₄ series has been performed. It is shown that reported level energies of the 6snd^1,3D₂ series are systematically 0.14 cm^?1 too high.     

Stark effect investigations of the 4f 14 6s 6p 3 P 1 and1 P 1 levels of ytterbium

The tensor polarizabilities of the 4f ¹⁴ 6s 6p ³ P ₁ level were investigated for all stable Ytterbium isotopes by the method of optical double resonance. The tensor polarizabilities were deduced from the rf-resonance signals in parallel electric and magnetic fields. The value obtained for the even Yb isotopes is in good agreement with the results derived from the measurements on the odd isotopes. The mean value isα _ten(³ P ₁)0=5.99(34)kHz/(kV/cm)². The tensor polarizability of the 4f ¹⁴ 6s 6p ¹ P ₁ level of¹⁷¹Yb was measured by means of the level crossing technique with parallel electric and magnetic fields. The experimental result isα _ten(¹ P ₁)=?14.3(1.4)kHz/(kV/cm)². This is compared with the prediction of the LS coupling approximation using the experimental data of the³ P ₁ level. Only poor agreement is obtained which is due to the configuration mixing in the¹P₁ level.     

Properties of the πη,$ \eta{^\prime}$,σ, f0(980) and a0(980) mesons and their relevance for the polarizabilities of the nucleon

The signs and values of the two-photon couplings F _Mγγ of mesons (M) and their couplings g_MNN to the nucleon as entering into the t -channel parts of the difference of the electromagnetic polarizabilities (α - β) and the backward angle spin polarizabilities γ_π are determined. The excellent agreement achieved with the experimental polarizabilities of the proton makes it possible to make reliable predictions for the neutron. The results obtained are α_n = 13.4±1.0 , β_n = 1.8±1.0 (10^-4fm^3), and γ⁽ⁿ⁾ _π = 57.6±1.8 (10^-4fm^4). New empirical information on the flavor wave functions of the f ₀(980) - and the a ₀(980) -meson is obtained.     

Polarizability of the fine-structure components of low excited states of the F, Cl, and Br atoms

The dynamic scalar, tensor, and pseudovector polarizabilities of the low excited states (ns)⁴ P _J of the F, Cl, and Br atoms (n = 3, 4, and 5, respectively) are calculated for all the levels of the fine-structure multiplets with J = 5/2, 3/2, and 1/2 with the use of the quantum detect Green’s function, proposed earlier.     

Tensor polarizabilities and lifetimes of levels of the configurations 4f 66s6p and 4f 55d6s2 in samarium I

Stark splittings of 7 levels of the configurations 4f ⁶6s6p and 4f ⁵5d6s² in Sm I were measured by quantum beat spectroscopy in pure electric fields, allowing the determination of tensor polarizabilities. Additionally, the lifetimes of 11 levels of these configurations were determined from time-resolved registration of the exponential decay. From these values the radial integrals I(6p,6s), I(6p,5d), and I(5d,4f) were derived by a parametric analysis. Theoretical values of tensor polarizabilities and lifetimes which were calculated using these radial integrals show good agreement with experimental data of various authors.     

Direct observation of the second-order Stark effect of theX-B transition in molecular iodine

The second-order Stark shift of the components of the hyperfine structure of the transition¹ _g ⁺ ( = 0,j = 13, 15) ³ _ou ⁺ ( = 43,j = 12, 16) (of molecular iodine have been studied by means of saturated absorption spectroscopy in an external cell with the I₂ vapour located in an electric field. The anisotropic polarizabilities of the upper and lower levels together with the difference between the isotropic polarizabilities of the levels of the transition have been obtained.     

Determination of tensor polarizabilities in Yb and Sm by quantum beat spectroscopy

Tensor polarizabilities of the levels 4f¹⁴6s6p³P₁ in Yb and (4f⁶6s6p+4f⁵5d6s²)⁷D₁,⁷F₁,⁷G₁ in Sm were deduced for the even isotopes from the modulation frequency of quantum beat signals.     

Tensor polarizabilities of levels of the configurations 4f 13 6s6p and 4f 12 5d6s 2 in thulium I

The level-crossing technique with parallel electric and magnetic fields was used to measure the tensor polarizabilities of six levels of the configuration 4f ¹³ 6s6p + 4f ¹² 5d6s ² in the Tm I-spectrum. Using intermediate coupling wave functions given by Camus and the experimental values of the tensor polarizabilities, the radial integrals for electric dipole transitions from levels of the configuration 4f ¹³6s6p + 4f ¹²5d6s ² to levels of the configuration 4f ¹³ 5d6s + 4f ¹² 6s ²6p have been determined. The results areI(4f ¹³6s6p,4f ¹³5d6s)=1.98(45)ea ₀ andI(4f ¹²5d6s ²,4f ¹²6s ²6p) = 0.88(25)ea ₀. A comparison between the experimental and the calculated values of the tensor polarizabilities shows an excellent agreement, provided that these radial integrals and the radial integrals for the electric dipole transitions to the ground state configuration 4f ¹³6s ² as determined by Wallenstein from lifetime measurements are used in the calculation, instead of radial integrals computed by Camus with Hartree-Fock wave functions.     

Polarizabilities of confined two-electron systems: the 2-electron quantum dot,the hydrogen anion,the helium atom and the lithium cation

The static dipole polarizabilities of two-electron systems confined by a spherical harmonic-oscillator potential?ω?have been calculated by the coupled-cluster CCSD method. The combined effect of the confining potential?ω?and the central electrostatic field on the polarizabilities of the quantum dot, and the confined systems, H^?, He and Li⁺, respectively, have been investigated. The polarizabilities of the quantum dot can be calculated analytically. The polarizability?α?of the 2-electron quantum dot for ω?=?0.01 is calculated to be 19?996?au, in perfect agreement with the exact value, 20?000?au. Already medium confinement, ω?=?1.0, reduces?α?to 2.00?au. The decrease of the polarizability is smaller for H^? (α?=?216.1?au for ω?=?0.0 and 0.985 au for ω?=?1.0), and much smaller for He and Li⁺ (1.3819 and 0.3813?au for He for ω?=?0.0 and ω?=?1.0, respectively, and 0.1921 and 0.128?au for Li⁺). The theoretical polarizabilities for unconfined (ω?=?0.0) H^?, He and the Li⁺ cation are in very good agreement with the best published theoretical and/or experimental data. Our final polarizability for H^?, 216.0±0.5?au, appears to be one of the most accurate values published so far. The optimization procedures of basis sets applicable to calculations of polarizabilities of systems confined by a spherical harmonic-oscillator potential are presented.     

Observation of giant polarizabilities in atomic sodium Rydberg states

We have observed by quantum beat spectroscopy the Stark effect in a low electric field of highly excited Na nD states (n = 10, 11, 12). The polarizabilities are found to be 10⁶ to 10⁷ time larger than those of atoms in ground or low lying excited states and are in good agreement with theoretical values calculated from a hydrogenic model.     

The dipole polarizability of the hydrogen molecular cation HD+ and other isotopomers

Fully non-adiabatic calculations are reported of the electric dipole polarizabilities for the N = 0 and N = 1 levels of the ground electronic states of H⁺ ₂ (ν ≤ 16), D⁺ ₂ (ν ≤ 24) and HD⁺ (ν ≤ 20). For H⁺ ₂ (ν = 0, N = 0) the calculated value still differs from the experimental value; this difference cannot be explained by the inclusion of higher order contributions.     

Stark interaction in then s n p z 3 P 1 levels of zinc and cadmium

The tensor polarizabilities of then s n p z ³ P ₁ levels of Zn and Cd were measured using optical double resonance. From the rf-resonance signals in parallel electric and magnetic fields, the following tensor polarizabilities were deduced: Zn,α _ten(4s4pz ³ P ₁)=1.83(8) kHz/(kV/cm)²; Cd,α _ten(5s5pz ³ P ₁)=1.77(8) kHz/(kV/cm)². Theoretical values were calculated using Coulomb approximation. The results were then compared with previous theoretical and experimental values and, in addition, with values for Hg. Theoretical results obtained by a modified Sternheimer method (E.J. Robinson: J. Opt. Soc. Am.59, 782 (1969)) are in better agreement with the experimental values than the results of the Coulomb approximation calculations.     

Eu原子4f76s(7S)np系列自电离谱的观察和测定

用激光三步共振激发方法观察了Eu原子的自电离谱。测定了Eu原子偶宇称,能量在45740.3—47341.0cm^-1范围的75个能级位置,识别了收敛于Eull 4f⁷6s ⁷S₃的4f⁷6s(⁷S)np(n=12—46)的自电离里德伯系列。报道了这一系列在此能量范围的能级位置及量子亏损数据。 关键词：     

碱原子高里德堡态的极化率

本文使用一种具有解析解的原子唯象势模型,计算了碱原子Na,K,Rb,Cs里德堡(15≤n≤55)的标量和量极化率,计算结果与实验符合很好。还确定了极化率标度关系α=An^*7+Bn^*6中的系数A和B,由此关系外推所得结果也与实验很好地符合。 关键词：     

Oscillator strengths and polarizabilities of the hot-dense plasma-embedded helium atom

The effect of weakly coupled hot plasma environment on the oscillator strengths of the ultraviolet and visible series and the polarizabilities of helium has been investigated using variational highly correlated wave functions within the non-relativistic framework. The Debye shielding approach that admits a variety of plasma conditions is used to simulate the plasma effects. For each shielding parameter, dipole oscillator strengths are calculated for the 1 ¹S-n¹P (n=2, 3), 2 ¹S-2 ¹P, 2 ³S-n³P (n=2, 3) and 2 ^1,3P-n^1,3D (n=3, 4) transitions. The dipole and quadrupole polarizabilities for the ground He (1s²¹S) state are also reported for each screening parameter. Results obtained are useful in plasma diagnostic purposes besides several other applications.     

Ab initio calculations of multipole moments,polarizabilities and long-range interaction coefficients for the azabenzene molecules

Using LCAO-SCF wave functions on the monomers and a non-empirical Unsöld procedure for the second-order properties we have calculated the (2 ^l ) multipole moments (up to l=6), the (l,l') multipole polarizabilities (up to l + l' = 6) and the related long-range coefficients describing the electrostatic, induction and dispersion interactions for the different azabenzene molecules. The agreement with available experimental data is good, in particular for the dipole polarizabilities. The anisotropy of the long-range interaction potential is dominated by the electrostatic contributions, although the dispersion terms, especially the mixed-pole terms (l≠l') for even n (C₈, C₁₀), also contribute significantly; the induction energy is rather small. The π contributions to the polarizabilities and the dispersion interactions are found to be larger than earlier estimates. Moreover, it is shown by calculating the dipole polarizabilities of some (aza)naphthalenes and (aza)anthracenes, that a bond polarizability model can be applied effectively only if the delocalized π electrons are considered separately from the σ electrons.     

Quantum Associative Neural Network with Nonlinear Search Algorithm

Based on analysis on properties of quantum linear superposition, to overcome the complexity of existing quantum associative memory which was proposed by Ventura, a new storage method for multiply patterns is proposed in this paper by constructing the quantum array with the binary decision diagrams. Also, the adoption of the nonlinear search algorithm increases the pattern recalling speed of this model which has multiply patterns to O( log₂^{2n -t} ) = O( n - t )O( {\log_{2}}^{2^{n -t}} ) = O( n - t ) time complexity, where n is the number of quantum bit and t is the quantum information of the t quantum bit. Results of case analysis show that the associative neural network model proposed in this paper based on quantum learning is much better and optimized than other researchers’ counterparts both in terms of avoiding the additional qubits or extraordinary initial operators, storing pattern and improving the recalling speed.     

Anisotropy of the lattice vibrations of 2HPbI2

In this paper an explanation is given of the observed large anisotropy of the static dielectric constant of 2HPbI₂ (?_0\t] = 26.4; ?_0| = 8.7). The optical modes of 2HPbI₂ are analysed in terms of long range Coulomb interactions. The results demonstrate the rather ionic nature of this compound. The polarizabilities of the I^? and the Pb²⁺ ions obtained from the optical data are 7.2 and 4.0 × 10^?24 cm³, respectively. The (Szigeti) effective charge is about 70% of the ionic charge. The anisotropy of the optical modes is caused mainly by static dipoles induced in the iodine ions by the anisotropic charge distribution in the crystal.