Search

In this paper we report a wave-function visualization of the core-induced interaction of a non-hydrogenic Rydberg atom in an electric field and its resultant redistribution of the spectral line intensities. The energy levels and oscillator strengths are calculated based on an effective potential where the radial part of the wavefunction is expanded in a B-spline basis. The calculation is in good agreement with the experimental measurements of the absorption spectrum of sodium atoms in an electric field of F = 840 V/cm, both below and above the saddle point [E.sub.sp]. The visualization of the wavefunction for the eigenstates can help us to see how they stem from the interaction between two or more red and blue hydrogenic states. An approximate localized symmetry close to the atomic core is also observed in the wavefunctions, which accounts for the alternation of oscillator strengths in the experiment. Key words: Rydberg atom, Stark effect, oscillator strength, symmetry. Nous presentons ici une visualisation par la fonction d'onde de l'interaction induite par le coeur d'un atome de Rydberg non hydrogenique dans un champ electrique, ainsi que la redistribution des intensites des raies spectrales qui s'ensuit. Nous calculons les niveaux d'energie et les forces d'oscillateur a partir d'un potentiel effectif, avec la partie radiale de la fonction d'onde ecrite dans une base B spline. Le calcul est en bon accord avec les valeurs experimentales du spectre d'absorption d'atomes de sodium dans un champ electrique de F = 840 V/cm, a la fois sous et au dessus du point de selle [E.sub.sp]. La visualisation des fonctions d'onde des etats propres peut nous aider a voir comment elles emergent d'une interaction entre deux ou plus d'etats hydrogeniques rouges et bleus. Nous observons aussi dans la fonction d'onde une symetrie locale approximative pres du coeur atomique, ce qui explique l'alternance des forces d'oscillateur dans l'experience. [Traduit par la Redaction] Mots-cles : atome de Rydberg, effet Stark, force d'oscillateur, symetrie. PACS Nos.: 32.60.+i, 32.70.Cs, 32.80.Fb., 1. Introduction Ever since the pioneering work on the Stark spectra of alkali metal atoms by Zimmerman et al. [1], the effect of an electric field on non-hydrogenic atoms in [...]

A theoretical treatment, using the first Born approximation, is presented to analyse the results of relativistic laser-assisted Proton--hydrogen atom scattering. Specific calculations are carried out for excitation of hydrogen atoms from 1[s.sub.[1/2]] to 2[s.sub.[1/2]] states by proton impact. We work in an approximation in which the incoming proton may be described by Dirac-Volkov states in the presence of a laser field. Semi-relativistic Darwin wave functions are used to describe the hydrogen atom in its initial and final states, while relativistic, spin, and laser interaction effects are also accounted for. The results presented in this paper show that the differential cross section for this process depends not only upon the energy of the incident proton, but also upon its interaction with the laser field through intensity and frequency. Key words: laser assisted, QED calculations, Dirac equation, relativistic atomic process, Dirac algebra. Nous presentons un calcul en premiere approximation de Born, pour analyser les resultats de diffusion proton-atome d'hydrogene en regime relativiste, sous l'influence d'un champ laser. Nos calculs sont specialises fi l'excitation d'un atome d'hydrogene du 1[s.sub.[1/2]] au 2[s.sub.[1/2]] par impact de proton. Nous travaillons dans l'approximation oU le proton peut etre decrit par des etats de Dirac-Volkov en presence d'un champ laser. Des fonctions d'onde semi-relativistes de Darwin sont utilisees pour decrire l'atome d'hydrogene dans ses etats initial et final, tout en tenant compte des effets relativistes, de spin et d'interaction laser. Les resultats presentes ici montrent que la section efficace differentielle pour ce processus depend non seulement de l'energie du proton incident, mais aussi de son interaction avec le champ laser via son intensite et sa frequence. [Traduit par la Redaction] Mots-cles : processus atomique relativiste assiste par laser, calculs EDQ/QED. PACS Nos.: 34.80.Dp, 12.20.Ds., 1. Introduction Analysis of inelastic proton-atom and proton-molecule scattering at intermediate to high energies has recently attracted a considerable amount of interest. In the case of electron- or positron-impact, relativistic [...]

In this paper, the Schrodinger equation for quaternionic quantum mechanics with a Dirac delta potential has been investigated. The derivative discontinuity condition for the quaternionic wave function has been derived and the boundary conditions for the quaternionic wave function have been applied. Probability current densities for different regions of the problem have been determined along with reflection and transmission coefficients. Key words: quaternionic quantum mechanics, Dirac delta potential, Schrodinger equation, reflection and transmission coefficients. Nous etudions ici l'equation de Schrodinger pour la mecanique quantique des quaternions avec un potentiel en fonction delta. Nous derivons la condition de discontinuite derivative pour la fonction d'onde de quaternion et appliquons les conditions limites a cette fonction d'onde. Les densites de courant de probabilite sont evaluees pour differentes regions du probleme et de meme pour les coefficients de reflexion et de transmission. [Traduit par la Redaction] Mots-cles : mecanique quantique des quaternions, potentiel en fonction delta, equation de Schrodinger, coefficients de reflexion et de transmission. PACS Nos.: 02.30.Tb, 03.65.Ca., 1. Introduction It is well-known that quaternions were discovered for the first time by Sir William Rovan Hamilton in 1843. They are suitable options to express some classical phenomena. The [...]

Observation of two separated beam spots at a detection screen downstream of a Stern-Gerlach magnet does not, in fact, demonstrate that the wavefunction of a neutral spin one-half particle has remained in a spin superposition while travelingthrough that magnetic field. The wavefunction may have been reduced to just one spin-direction eigenfunction, as D. Bohm suggested, by immediate momentum and energy transfer with the magnet, rather than by subsequent, which-way determination at the screen. The same two beam spots at the detector screen will result. Einsteinian relativity, and the understanding of Schrodinger evolution applicability through a static potential, forbid continuation of a spin superposition through the SternGerlach field. A calculation for single wavepacket development there conforms to observations from the Stern-Gerlach experiment. And several experiments corroborate immediate reduction to a single spin eigenfunction in the magnetic field. Additionally, Ramsey's separated, oscillating fields observations, and related experiments, do not rebut this understanding. PACS Nos.: 03.65.Ta, 03.65.-w. L'observation de deux spots de faisceau separes sur un ecran detecteur derriere un aimant de Stern-Gerlach ne demontre pas, en fait, que la fonction d'onde d'une particule neutre de spin un demi est demeuree une superposition de spin en traversant le champ magnetique. La fonction d'onde peut avoir ete reduite a une fonction propre d'une seule direction de spin, comme l'avait propose D. Bohm, par transfert immediat d'impulsion et d'energie avec l'aimant, plutot que par une determination subsequente de la direction par l'ecran. La relativite d'Einstein et la loi d'evolution de Schrodinger a travers un potentiel statique interdisent le maintien d'une superposition de spin a travers le champ de Stern-Gerlach. Un calcul pour un simple paquet d'onde dans ces conditions confirme les observations de l'experience de Stern-Gerlach. Plusieurs experiences corroborent la reduction immediate vers la fonction propre d'une seule direction de spin dans le champ magnetique. De plus, la separation de Ramsay dans l'observation des champs oscillants, et des experiences du meme type, ne refutent pas ce point de vue. [Traduit par la Redaction], 1. Introduction The familiar Stern-Gerlach (S-G) experiment [1, 2] conceived more than 90 years ago, has remained a ubiquitous pedagogical paradigm and the canonical model for quantum measurement ever since. [...]

Light front holography is a formalism developed by Brodsky and de Teramond in which analytic forms for the hadronic bound state wavefunctions can be obtained. We have used the holographic light front wavefunctions thus obtained to calculate the distribution amplitudes of the light vector mesons ρ and [K.sup.*]. As a result, we are able to calculate the form factors for B → ρ, [K.sup.*] transitions as well as Δ.sub.QCD]/[m.sub.b] contributions in radiative [B.sub.(s)] [right arrow] [(ρ, [K.sup.*]).sub.γ] decays. We compare our predictions to the available experimental data. PACS Nos.: 12.38.Aw, 11.25.Tq, 13.20.He, 14.40.Nd. L'holographie QCD est un formalisme developpe par Brodsky et de Teramond dans lequel nous pouvons obtenir une forme analytique pour les fonctions d'onde des etats hadroniques lies. Nous appliquons ce formalisme pour obtenir les fonctions d'onde necessaires au calcul des amplitudes de distribution des mesons vecteurs legers ρ et [K.sup.*]. Par la suite nous sommes capables d'evaluer les facteurs de forme des transitions B → ρ, [K.sup.*], ainsi que les contributions radiatives [Δ.sub.QCD]/[m.sub.b] des desintegrations [B.sub.(s)] [right arrow] [(ρ, [K.sup.*]).sub.γ]. Nous comparons nos predictions avec les donnees experimentales disponibles. [Traduit par la Redaction], 1. Introduction Flavor-changing neutral currents are excellent probes to the Standard Model and beyond. In particular, the b → (s, d)γ and b → (s, d)[l.sup.+][l.sup.-] transitions, where l = [...]

Energy levels, wavefunction compositions, and lifetimes are computed for all levels of 4[s.sup.2]4[p.sup.5], 4[s.sup.2]4[p.sup.4]4d, and 4s4[p.sup.6] configurations in Br-like ions (Z = 47-50). We use the multiconfigurational Dirac-Fock method to generate the wavefunctions. We also present the transition wavelengths, oscillator strengths, transition probabilities, and line strengths for the electric dipole (E1) transition from the ground state configuration. We compare our calculated results with the available data in the literature and good agreement is obtained, which confirms the quality of our results. Moreover, we predict some new atomic data that have not been available so far and may be important for plasma diagnostic analysis in fusion plasma. PACS No.: 32.70.Cs. Nous calculons tous les niveaux d'energie, les fonctions d'onde et les temps de vie de tous les niveaux des configurations 4[s.sup.2]4[p.sup.5], 4[s.sup.2]4[p.sup.4]4d et 4s[4.sup.p6] dans les ions de type Br (Z = 47-50). Nous utilisons la methode multi-configurations de Dirac-Fock pour generer les fonctions d'onde. Nous presentons egalement les longueurs d'onde de transition, les forces d'oscillateur, les probabilites de transition et les intensites de raie pour les transitions dipolaires electriques (E1) a partir de la configuration du fondamental. Nous comparons nos resultats avec ceux existant dans la litterature et trouvons un tres bon accord, ce qui confirme la qualite de nos resultats. Nos resultats s'etendent a de nouvelles donnees atomiques qui n'etaient pas disponibles jusqu'a aujourd'hui et qui pourraient etre importantes pour l'analyse diagnostique des plasmas de fusion. [Traduit par le Redaction], 1. Introduction Oscillator strengths and transition probabilities are important parameters in atomic spectroscopy as they include information about the selection of relevant transitions and atomic concentration in plasma environments. Atomic [...]

The problem of relativistic particles moving in the background of a weak gravitational plane wave is solved by the use of Parisi-Wu stochastic quantization method. After having solved the corresponding Langevin equations, we have calculated exactly the correlation product of two fields known as a Green's function at the thermal-equilibrium limit for the fictitious time. By addition of an infinitesimal imaginary part of the mass, the existence of the limit of the correlation function at the equilibrium is assured. Analytical and exact expressions of the wave functions are obtained both for Klein-Gordon (KG) and Dirac particles. PACS Nos: 04.30.-w, 5.10.Gg, 03.65.Ca, 03.65.Pm Nous solutionnons le probleme de particules relativistes dans un champ externe constitue d'onde planes gravitationnelles faibles, a l'aide de la methode de quantification stochastique de Parisi-Wu. Apres avoir resolu l'equation de Langevin correspondante, nous avons calcule exactement le produit de correlation de deux champs connus comme la fonction de Green et la limite d'equilibre thermique pour le temps fictif. Par l'addition d'une partie imaginaire infinitesimale a la masse, nous garantissons l'existence d'une limite a la fonction de correlation a l'equilibre. Nous obtenons des expressions analytiques et exactes pour des particules de Klein-Gordon et de Dirac. [Traduit par la Redaction], 1. Introduction The propagators of relativistic particles interacting with external fields of various natures provide us with important information about the quantum behavior of these particles. What explains the increased [...]

The formalism of path integral is used to treat the influence of Stark shift on the atomic population inversion (API) and Pancharatnam phase in the Jaynes-Cummings model with a nonlinear Kerr cavity. The propagators are given explicitly as perturbation series. In the case of a quantized wave interacting with a two-level system, these are summed up exactly, and the corresponding Pancharatnam phase as well as atomic population inversion, and energy spectrum with corresponding wave functions are deduced. PACS Nos: 03.30.+p, 03.65.Pm, 03.65.Ge, 03.65.Db Nous utilisons le formalisme des integrales de parcours pour etudier l'influence du deplacement de Stark sur les inversions de populations atomiques (API) et la phase de Pancharatnam dans le modele de Jaynes--Cumings avec une cavite non lineaire de Kerr. Les propagateurs apparaissent explicitement sous la forme de series perturbatives. Dans le cas de l'onde quantique en interaction avec un systeme a deux niveaux, elles sont sommees exactement et nous en deduisons la phase correspondante de Pancharatnam et les inversions de population, ainsi que le spectre en energie avec les functions d'onde correspondantes. [Traduit par la Redaction], 1. Introduction The geometric phase acquired by a quantum system during a cyclic and adiabatic, or noncyclic and nonadiabatic evolution has led to numerous writings [1-5] and several applications [6-8]. [...]

A new scalar diffraction modeling method for simulating the readout signal of optical disks is described. The information layer is discretized into pixels that are grouped in specific ways to form written and unwritten areas. A set of 2D wave functions resulting from these pixels at the detection aperture is established. A readout signal is obtained via the assembly of wave functions from this set according to the content under the scanning spot. The method allows efficient simulation of jitter noise due to edge deformation of recorded marks, which is important at high densities. It is also capable of simulating a physically irregular mark, thereby helping to understand and optimize the recording process. OCIS codes: 210.0210, 210.4590, 260.1960.

An alternative analysis technique, which does not require eigensolutions as a priori, for the dynamic response solutions, in terms of the transfer function, of one-dimensional distributed parameter systems with arbitrary supporting conditions, is presented. The technique is based on the fact that the dynamic displacement of any point in a waveguide can be determined by superimposing the amplitudes of the wave components traveling along the waveguide, where the wave numbers of the constituent waves are defined in the Laplace domain instead of the frequency domain. The spatial amplitude variations of individual waves are represented by the field transfer matrix and the distortions of the wave amplitudes at point discontinuities due to constraints or boundaries are described by the wave reflection and transmission matrices. Combining these matrices in a progressive manner along the waveguide using the concepts of generalized wave reflection and transmission matrices leads to the exact transfer function of a complex distributed parameter system subjected to an externally applied force. The transient response solution can be obtained through the Laplace inversion using the fixed Talbot method. The exact frequency response solution, which includes infinite normal modes of the system, can be obtained in terms of the complex frequency response function from the system's transfer function. This wave-based analysis technique is applicable to any one-dimensional viscoelastic structure (strings, axial rods, torsional bar, and beams), in particular systems with multiple point discontinuities such as viscoelastic supports, attached mass, and geometric/material property changes. In this paper, the proposed approach is applied to the flexural vibration analysis of a classical Euler-Bernoulli beam with multiple spans to demonstrate its systematic and recursive formulation technique. [DOI: 10.1115/1.2424972]

Research has been conducted on role of ab initio molecular dynamics in the biological systems. The use of the density functional theory and plane wave basis set as the foundation of the ab initio molecular dynamics is described.

Nine formulations of nonrelativistic quantum mechanics are reviewed. These are the wavefunction, matrix, path integral, phase space, density matrix, second quantization, variational, pilot wave, and Hamilton-Jacobi formulations. Also mentioned are the many-worlds and transactional interpretations. The various formulations differ dramatically in mathematical and conceptual overview, yet each one makes identical predictions for all experimental results. [DOI: 10.1119/1.1445404]

The singlet-singlet electronic spectrum of the anti conformer of n-tetrasilane is studied using multiconfigurational wave functions (CASSCF), second-order perturbation theory (CASPT2), and its multi-state extension (MS-CASPT2) in conjunction with large ANO-type basis sets including Rydberg functions. The results are consistent with the available experimental data and are easily understood in terms of a simple Huckel model of sigma-delocalization.

The wavelet transform is introduced as a powerful tool for monitoring power quality problems generated due to dynamic performance of industrial plants. The paper presents a multiresolution signal decomposition technique as an efficient method in analyzing transient events. The multiresolution signal decomposition has the ability to detect and localize transient events and furthermore classify deferent power quality disturbances. It can also be used to distinguish among similar disturbances. Keywords: Power quality, wavelet analysis, and multiresolution signal decomposition.

A study was conducted to examine possible energy surfaces of the lowest singlet and triplet states in the titanium hydride, Ti2H6. Wave functions were utilized to describe a reference state for the Ti2H6 isomers. Results indicated that the lowest energy isomer was the triple Cs structure supporting an exothermic dimerization energy of 56.4 kcal/mol on the classical ground-state potential energy surface.

The intermixing-induced blueshift of the quantum well ground state interband transitions was notably improved in wave-function engineered heterostructures. The largest enhancements were attained in the thin potential notch at the center of the well combined with thin potential spikes on the edge of the well. The blueshift enhancement was shown to be potentially effective in minimizing the amount of defects. Intermixing, on the other hand, should be employed in the modification of the properties of the optoelectronic devices.

The different methods used in the past to theoretically explain nonadiabatic many-particle systems were examined and a new nonadiabatic method was suggested. The nonadiabatic methods of the past reveal that as the number of particles increase, the amount of complications in calculations increase correspondingly. The many-body nonadiabatic problem was simplified by withholding the Cartesian co-ordinate frame rather than changing the problem to the Cal coordinate frame.

Mixed-valance binuclear complexes reveal electronic coupling which can be extensively comprehended by adopting the uncomplicated theoretical outline derived from the Mulliken model for donor-acceptor reactions. Changes which are artificially incorporated yield information about the electrochemical potential shift. Ordinary dimeric structures reveal a resonance delocalization energy which are determined along with the extent of quantum coupling by the data obtained. The wave function coefficient is used to calculate the magnitude of wave function mixing.

A study conclusively proves that the protonitronium dication HONO2+ is definitely a metastable molecule in the gas phase having a minimal lifetime of 2 times 10 to the power of minus 5 s, but the dication can be generated only from dissociative electron impact ionization of appropriate neutral precursors. The hostile Franck/Condon elements preclude the direct production through ionization of the HONO+ monocation by a charge-stripping mechanism. Ab initio computations using extremely correlated wave functions complement and reinforce the experimental results. The commonly employed method of using many-body perturbation theory based on a single determinant to explain electron correlation is inappropriate in this case because of the unique nature of the charge separation fragmentation reactions in dications despite the static areas being closed-shell singlets.

A large sample of molecules of the first- and second- row elements is studied using the electronic structure theory at correlated levels and the d function contributions are compared with results using the Hartree-Fock level. The sample is subjected to configuartion interaction calculations and results suggest that the d function's polarizing role in the Hartree-Fock part of the wave function is suplemented by a mainly angular correlating role.

Researchers used many-electronic wave functions to measure the electronic coupling between the copper atoms in an azmin dimer. The rate measurements of electron self-exchange between two azmins are consistent with the rates measured experimentally. Results also indicate the significance of water molecules as switches for the biological electron transfer.

A study was conducted to assess the applicability of plane-wave density functional calculations to model clusters comprised of about 100 transition-metal atoms to mimic larger experimentally treated particles. The findings for high performance of the plane-wave calculations for transition-metal nanoparticles could be applied to design and study realistic models of catalytic systems.

A fast wavelet transform (FWT) is applied to obtain highly sparse moment-method matrix equations from an integral equation formulation of the electromagnetic wave scattering by conducting bodies of revolution. These equations are solved by the generalized minimal residual (GMRES) method and numerical experiments are presented to illustrate the efficiency of the proposed solution technique. Index Terms--Wavelet transforms, wave scattering.