429 research outputs found
The spin dependence of the excitation of metastable autoionising lithium 4P states by electron impact
No full textBaum G, Raith W, Schröder W. The spin dependence of the excitation of metastable autoionising lithium 4P states by electron impact. J.Phys. B. 1988;21(16):L501-L507
Measurement of spin asymmetries in the electron impact ionisation of alkali atoms
No full textBaum G, Moede M, Raith W, Schröder W. Measurement of spin asymmetries in the electron impact ionisation of alkali atoms. J.Phys. B. 1985;18(3):531-538
Measurement of the scalar polarizability of very highly excited states of caesium
No full textvan Raan AFJ, Baum G, Raith W. Measurement of the scalar polarizability of very highly excited states of caesium. J.Phys. B. 1976;9(12):L349-L352.First results on the scalar polarizability alpha 0 of a number of very highly excited p states of Cs (40 109 Å3 were measured; the dependence of the polarizability as a function of the principal quantum number n was found to be in agreement with the expected n7 behaviour
Spin-dependent electron impact ionisation of lithium from threshold to 80 eV
No full textBaum G, Kisker E, Raith W, Schröder W, Sillmen U, Zenses D. Spin-dependent electron impact ionisation of lithium from threshold to 80 eV. J.Phys. B. 1981;14(22):4377-4388.The ionisation asymmetry is measured in a crossed-beam experiment utilising a W/EuS field emitter as a source of polarised electrons and dual-frequency optical pumping as the polarising process for the lithium atomic beam. The antiparallel-parallel asymmetry of the total ionisation cross section is positive with a broad maximum of 0.35 near threshold and a gradual decrease towards higher energies. A comparison is made with results of binary encounter and Born approximations. At threshold no significant variation of the asymmetry with energy is observed within a resolution of 0.3 eV
The temperature dependence of the spin polarization of field emitted electrons from a W-EuS-vacuum junction
No full textBaum G, Kisker E, Mahan AH, Schröder K. The temperature dependence of the spin polarization of field emitted electrons from a W-EuS-vacuum junction. Journal of Magnetism and Magnetic Materials. 1976;3(1-2):4-6.We have measured the temperature dependence P(T) of the electron spin polarization of field emitted electrons from a W-EuS-vacuum junction. The shapes of the P(T) curves depend strongly on the annealing temperature of the EuS layer. Annealed at some temperature between 300°C and 600°C the polarization drops to zero at about 16 ± 2 K
Damage Control Resuscitation of the exsanguinating trauma patient: pathophysiology and basic principles
No full textEamon Raith, Claire Frauenfelder, William Grigg
Exchange in Electron-Impact Ionization - Triple Differential Measurements with Polarized Beams
No full textFrost L, Baum G, Blask W, Freienstein P, Hesse S, Raith W. Exchange in Electron-Impact Ionization - Triple Differential Measurements with Polarized Beams. In: Electronic and Atomic Collisions. 1992: 655-664
Production of a spin-polarized, metastable He(23 S) beam for studies in atomic and surface physics
No full textBaum G, Raith W, Steidl H. Production of a spin-polarized, metastable He(23 S) beam for studies in atomic and surface physics. Z.Phys. D. 1988;10(2-3):171-178.This beam was developed as a target for a crossed-beam electron-atom scattering experiment on the interaction of a polarized spin-1/2 electron with a polarized spin-1 atom. In the future this beam will be used in "Spin-Polarized Metastable Atom Deexcitation Spectroscopy" (SPMDS) for studying ferromagnetic surfaces without and with adsorbate layers. We use a discharge source for producing a beam of metastable helium atoms, a permanent sextupole magnet with a central stop at its exit for selecting He(2^3 S) atoms in the Zeeman substate ms=+1, a zero-field spin flipper for reversing the atomic beam polarization with respect to a magnetic guiding field, and a Stern-Gerlach magnet for analyzing the atomic polarization. At a distance of 90 cm beyond the exit of the sextupole, in the "interaction region" of an experiment, the polarized beam has a circular cross section of about 6 mm FWHM and a particle density of 1·10^7 atoms/cm^3. The reversible spin polarization was determined asP=0.90±0.02. A possible contamination of the beam with metastable singlet atoms is included within this value; the ground-state He atoms are not considered to be part of the polarized beam. An observed contamination with long-lived Rydberg atoms can easily be destroyed by applying a high electric field
Measurement of spin observables in electron scattering from atoms and nucleons
No full textBaum G, Raith W. Measurement of spin observables in electron scattering from atoms and nucleons. In: Campbell DM, Kleinpoppen H, eds. Selected Topics on Electron Physics. Physics of Atoms and Molecules. New York : Plenum Press; 1996: 15-30
Interference effects between electron exchange and the spin-orbit interaction
No full textRaith W, Baum G, Tondera M. Interference effects between electron exchange and the spin-orbit interaction. In: Canadian Journal of Physics. Canadian Journal of Physics. Vol 74. Natl. Research Council Canada; 1996: 883-888.In accordance with predictions made in 1974, recent measurements demonstrated that the elastic e-Cs scattering is richer in physics than a simple addition of Mott scattering and nonrelativistic exchange would provide. Now it is time to take a closer look at the general analysis of Burke and Mitchell and think about further experiments that will stimulate improvements in calculations and lead to a deeper understanding of the underlying physics
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