Spin polarization of light atoms in jellium: Detailed electronic structures

We revisit the problem of the spontaneous magnetization of an {\em sp} impurity atom in a simple metal host. The main features of interest are: (i) Formation of the spherical spin density/charge density wave around the impurity; (ii) Considerable decrease in the size of the pseudoatom in the spin-polarized state as compared with the paramagnetic one, and (iii) Relevance of the electron affinity of the isolated atom to this spin polarization, which is clarified by tracing the transformation of the pseudoatom into an isolated negative ion in the low-density limit of the enveloping electron gas.Comment: 4 pages, 4 figures, accepted to Phys. Rev.

Resonance structure in low-energy electron scattering from OCS

Energy-dependent absolute angle-differential cross sections (θ = 135°) for elastic and vibrationally inelastic electron scattering from OCS molecules have been investigated at high resolution (13 meV). The elastic cross section, reported over the range E= 0.06–20 eV, exhibits a deep Ramsauer–Townsend minimum near 0.55 eV and the π*(1.2 eV) and σ*(3.8 eV) resonances known from earlier experimental and theoretical work. The excitation functions for vibrational excitation (VE) of the fundamental CS stretch (1 0 0), the CO stretch (0 0 1) as well as for the fundamental and harmonics of the bending (0 n 0) mode are reported from threshold up to E = 8 eV. VE is mediated—in part in a mode-selective way—by threshold peaks and the higher lying resonances. The selectivity in the threshold region can be rationalized in terms of symmetry arguments where the ²Σ virtual state excites preferentially the σ vibrational states with even quanta of bending vibration over the π vibrational states with odd quanta of bending vibration. The σ*CS resonance is essentially inactive in VE of the CO stretch and the bending mode

Elastic scattering, vibrational excitation, and attachment in low-energy electron-SF₆ scattering: Experiment and effective range theory

Cross sections at low energies for vibrationally elastic and inelastic scattering, as well as electron attachment to SF₆, have been calculated using a multichannel effective range theory (ERT) with complex boundary conditions. The most active vibrational modes, the totally symmetric mode ν1 and the infrared active mode ν3, have been included in the calculation. The ERT parameters were fitted to reproduce the experimental total and attachment cross sections. Differential elastic and vibrational excitation cross sections have been measured at 30° and 135° using a spectrometer with hemispherical analyzers. The calculation reproduces correctly the magnitudes and shapes of the differential elastic and ν1, ν3, and 2ν1 excitation cross sections, in particular the sharp structures at vibrational thresholds. The s- and p-wave phase shifts obtained in the present analysis differ from those recently derived by Field et al. [Phys. Rev. A, 69, 052716 (2004)]

Electron attachment to SF6 and lifetimes of SF6- negative ions

We study the process of low-energy electron capture by the SF6 molecule. Our approach is based on the model of Gauyacq and Herzenberg [J. Phys. B 17, 1155 (1984)] in which the electron motion is coupled to the fully symmetric vibrational mode through a weakly bound or virtual s state. By tuning the two free parameters of the model, we achieve an accurate description of the measured electron attachment cross section and good agreement with vibrational excitation cross sections of the fully symmetric mode. An extension of the model provides a limit on the characteristic time of intramolecular vibrational relaxation in highly-excited SF6-. By evaluating the total vibrational spectrum density of SF6-, we estimate the widths of the vibrational Feshbach resonances of the long-lived negative ion. We also analyse the possible distribution of the widths and its effect on the lifetime measurements, and investigate nonexponential decay features in metastable SF6-.Comment: 22 pages, 10 figures, submitted to Phys. Rev.

Regionale Kohortenstudie zur somatischen Klassifikation von Neugeborenen unter Berücksichtigung der Einflussfaktoren Nikotinkonsum, Body-Mass-Index, Gewichtszunahme der Schwangeren und Parität

Es wird eine regionale Kohorte von Neugeborenen im Bezug auf die Beeinflussung somatischer Geburtsparameter durch Rauchverhalten, BMI, Gewichtszunahme und Parität der Mutter sowie Schwangerschaftsdauer untersucht. Ergänzende Untersuchungen des Mikrozensus für MV und Deutschland zeigen die lokale Relevanz der Untersuchung zum Raucherinnenstatus. Die Ergebnisse zeigen, dass die somatischen Parameter deutlich durch den Nikotinkonsum der Mutter, den BMI und die Parität beeinflusst werden. Abschließend werden Möglichkeiten der Rauchprävention aufgezeigt

High resolution studies of low-energy electron attachment to SF5Cl: Product anions and absolute cross sections

Low energy electron attachment to SF$_5$Cl was studied at high energy resolution by mass spectrometric detection of the product anions. Two variants of the laser photoelectron attachment (LPA) technique (Kaiserslautern) were used for determining the threshold behaviour of the yield for SF$_5^-$ formation at about 1 meV resolution, and to investigate the relative cross sections for Cl$^-$, FCl$^-$, and SF$_5^-$ formation towards higher energies (up to 1 eV) at about 20 meV resolution. Thermal swarm measurements (Birmingham) were used to place the relative LPA cross sections on an absolute scale. A trochoidal electron monochromator (Innsbruck) was used for survey measurements of the relative cross sections for the different product anions over the energy range of 0-14 eV with a resolution of 0.30 eV. Combined with earlier beam data (taken at Berlin, J. Chem. Phys. 88 (1988) 149), the present experimental results provide a detailed set of partial cross sections for anion formation in low-energy electron collisions with SF$_5$Cl

Does Spin-Orbit Coupling Effect Favor Planar Structures for Small Platinum Clusters?

We have performed full-relativistic density functional theory calculations to study the geometry and binding energy of different isomers of free platinum clusters Pt$_{n}$ ($n=4-6$) within the spin multiplicities from singlet to nonet. The spin-orbit coupling effect has been discussed for the minimum-energy structures, relative stabilities, vibrational frequencies, magnetic moments, and the highest occupied and lowest unoccupied molecular-orbital gaps. It is found in contrast to some of the previous calculations that 3-dimentional configurations are still lowest energy structures of these clusters, although spin-orbit effect makes some planar or quasi-planar geometries more stable than some other 3-dimentional isomers

Three-photon detachment of electrons from the fluorine negative ion

Absolute three-photon detachment cross sections are calculated for the fluorine negative ion within the lowest-order perturbation theory. The Dyson equation of the atomic many-body theory is used to obtain the ground-state 2p wavefunction with correct asymptotic behaviour, corresponding to the true (experimental) binding energy. We show that in accordance with the adiabatic theory (Gribakin and Kuchiev 1997 {Phys. Rev. A} {\bf 55} 3760) this is crucial for obtaining absolute values of the multiphoton cross sections. Comparisons with other calculations and experimental data are presented.Comment: 10 pages, two figures, Latex, IOP styl

Rotational hybridization, and control of alignment and orientation in triatomic ultralong-range Rydberg molecules

We explore the electronic structure and rovibrational properties of an ultralong-range triatomic Rydberg molecule formed by a Rydberg atom and a ground state heteronuclear diatomic molecule. We focus here on the interaction of a Rb($n,l\geqslant 3$) Rydberg atom with a KRb(N = 0) diatomic polar molecule. There is significant electronic hybridization with the Rb(n = 24, $l\geqslant 3$) degenerate manifold. The polar diatomic molecule is allowed to rotate in the electric fields generated by the Rydberg electron and core as well as an external field. We investigate the metamorphosis of the Born–Oppenheimer potential curves, essential for the binding of the molecule, with varying electric field and analyze the resulting properties such as the vibrational structure and the alignment and orientation of the polar diatomic molecule.RGF gratefully acknowledges a Mildred Dresselhaus award from the excellence cluster 'The Hamburg Center for Ultrafast Imaging Structure, Dynamics and Control of Matter at the Atomic Scale' of the Deutsche Forschungsgemeinschaft and financial support by the Spanish Ministry of Science FIS2011-24540 (MICINN), grants P11-FQM-7276 and FQM-4643 (Junta de Andalucía), and by the Andalusian research group FQM-207. We also acknowledge financial support by the Initial Training Network COHERENCE of the European Union FP7 framework. HRS and PS acknowledge ITAMP at the Harvard-Smithsonian Center for Astrophysics for support