Streuung von Helium-Atomstrahlen in Edelgasen

The scattering of Helium atomic beams in rare gases is investigated by measurements of total elastic scattering cross sections. With the device described the dependence of total scattering cross sections of the relative velocity of the scattering atoms was measured. For variation of the beam velocity in the range of 1:8 a He beam source was used which could be cooled down with liquid helium from room temperature to 4.8 °K. The detector is of the universal-detector-type. A Wien filter is used as mass filter. The lowest detectable particle density is 6.3 · 10³ He-atoms/cm³. The measured scattering cross sections are in qualitative agreement with the theory ofBernstein.     

Streuung von Li+-Ionen an Edelgasen

The angular distribution of Li ₇ ⁺ -ions (7–60 keV) scattered by rare gas atoms (He, Ne, A, Kr, X) shows 3–5 characteristic maxima of intensity, which are not observed when electrons of equal energy are scattered by the same atoms. The existence of the maxima can be explained by polarization of the scattering rare gas atoms by the Li ₇ ⁺ -ions.     

Die Auger-Spektren derL 2- undL 3-Schale von Argon

TheL ₂ MM andL ₃ MM-Auger spectra of gaseous argon have been investigated with an electrostatic spectrometer with energy resolution of 0.17%. The ionization in theL ₂ andL ₃ shell was caused by electron impact. It was possible to separate allL ₂ MM andL ₃ MM lines except the components of transitions to triplet final states. The experimental relative intensities of transitions within theL ₂ M _2,3 M _2,3 andL ₃ M _2,3 M _2,3 groups agree well with theoretical values, calculated byRubenstein, whereas the relative intensities of transitions of the groupsL ₂ M ₁ M ₁,L ₃ M ₁ M ₁,L ₂ M ₁ M _2,3 andL ₃ M ₁ M _2,3 differ systematically from theoretical values.     

Die Geschwindigkeitsabhängigkeit totaler Streuquerschnitte von Alkalien an Edelgasen

The velocity dependence of the total scattering cross section has been measured for 10 different combinations of alkali atoms with rare gas atoms. By means of an automated fast comparison technique the precision of relative values ofQ(ν) can be increased to 10^?3. In the eight cases where Ar, Kr or Xe is the scattering gas, undulations ofQ(ν) about its mean value have been observed. The precision of the method allows us in these cases to extract reliable information on the amplitude of the undulations. Use of this additional information makes it impossible to explain the experimental results with the simple, 2- or 3-parameter potentials that are generally used. Deferring a final evaluation to a later paper, we restrict ourselves here to giving, for the Lennard-Jones (8?6) potential, a table of?r _m values.     

Zur Theorie der Streuung von Li 7 + -Ionen an Edelgasen

The angular distribution of Li ₇ ⁺ -ions scattered by rare gas atoms shows at scattering angles in the order of 10^?4<?<10^?3 rad characteristic maxima of intensity. These maxima cannot be explained by the electron scattering theory applying electrons equienergetic to the Li ₇ ⁺ -ions. Therefore the interaction potential between the scattered Li ₇ ⁺ -ions and the rare gas atom is extended in such a way, that the mutual action of the charge distributions of both systems is taken into account. A simple form for this potential gives positions of the maxima which are in good agreement with the experimental values.     

Totale Streuquerschnitte für den Stoß von H2, D2 und He an den Edelgasen Ne,Ar, Kr und Xe im thermischen Energiebereich

The velocity dependence of the total elastic cross section has been measured for the scattering of H₂, D₂, and He beams by Ne, Ar, Kr, and Xe gases. Velocity-selected beams were attenuated by gas in a scattering chamber. A universal detector, with a magnetic mass separator, was used in conjunction with lock-in techniques. The results are compared with quantum mechanical calculations using a Lennard-Jones-(12.6)-potential, and employing suitable averaging over experimental velocity distributions. Potential parameters are presented. These are in good agreement with those expected from other methods of measurement.     

Die Abweichungen von den Cauchy-Relationen

Qualitative rules for the deviations from the Cauchy relations are derived from experimental data. These departures are the components of a second rank tensor. The coefficients of “lateral interaction”c _iijj dominate in most cases over the correspondent shear resistancesc _ijij. Extreme effects of this type are generated by asymmetric lattice particles. Covalent bonds and other strong bonds with preferential orientation as well as strong overlap cause opposite effects. The departures from the Cauchy relations and the atomistic binding properties are very closely correlated.     

Über den Einbau von Fremdstoffen in Kristalle

Firstly, the site distribution of impurity phase, the grade of its dispersion and its chemism are mentioned, further, the various types of site distribution of impurities, first of all in the case of the isomorphism, are discussed in detail. The attention is paid to the anomalous site distribution if the valence electron states or the lattice energies of single partners are different, as well as to the site distribution with formation of vacancies or with additional occupation of vacancies. Finally, the cases of lattice sites occupation by ions of different valency, of partially isomorphous and multiply anomalous built-in of impurities are discussed.     

Über den Einbau von Nickel in die Alkalichloride

By means of the method of P. Brauer the energy of built in Ni⁺⁺-ions in the crystals of LiCl, NaCl and KCl was calculated. The results let understand the differences in the content of nickel in the mentioned crystals.

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Der Verfasser dankt herzlich Herrn Dr. K. Polák für die wertvollen Diskussionen und Bemerkungen zu dieser Arbeit, Frl. Dipl.-Ing. H. Svobodová für die Durchführung der numerischen Berechnungen und Herrn Dr. K. Funk für die Beistellung der Analysenergebnisse.     

Energieverluste schneller Lithium- und Natrium-Ionen bei Wechselwirkung mit Edelgasen

Li⁺- and Na⁺-ions (30 keV) interacting with rare gases show energy distributions with discrete and continious energy-losses. The smallest discrete energy-losses can be explained by excitation of the rare gas atom shell nearest to the ground state. Higher energy-losses can be explained by neutralization (charge exchange) and reneutralization connected with excitation of the neutral alcali-atom; this explanation is supported by spectroscopic measurements. Other discrete energy-losses can be described — not always uniquely — by several other excitation-, neutralization- and ionization-processes.     

Eine untersuchung über den einfluβ von lärm und psychischen faktoren auf den schlaf von patientinnen im krankenhaus

Using a questionnaire, an investigation was carried out among 240 patients in the maternity and gynaecological departments of eight West Berlin hospitals concerning their subjective sleeping quality of the night before and other psychic factors. At the same time the noise situation in their rooms was recorded for that night. It was found that the subjective quality of sleep did not correlate with the equivalent level. However, with regard to the differences between the 10% and 50% levels and the 10% and 90% levels, correlation proved highly significant. The equivalent levels ranged between 28 and 53 dB(A) and the level differences between 0 and 25 dB(A). The equivalent level is thus of no use as a criterion for forecasting probable disturbances of human sleep by noises at the levels investigated. It appears advisable, instead, to include in the relevant directions an additional reference to the effect that the difference between the 10 and 50% levels should not exceed 10 dB at night.     

Gasaufheizung und Energiebilanz einer stationären hochfrequenten Ringentladung in Edelgasen

Gasheating and Energy Balance of a Stationary High Frequency Ring Discharge in Rare Gases The energy balance of an inductively coupled high frequency (28,5 Mhz) discharge in a cylindrical vessel (11,2 cm diam.) in Ne, Ar, Kr, Xe at pressures between 0,1 and 10 Torr and at power inputs between 10 and 1000 W is investigated. The heat power transferred to the neutral gas in the stationary discharge is determined from the time behaviour of the neutral gas pressure in the afterglow period. The power measurements are completed by probe measurements of the electron density and energy distribution function. The measured electron energy distribution functions are maxwellian with a slight deficit electrons in the energy range of inelastic collisions. The electron temperatures show a rather low radial space dependence which can be explained on the basis of the local energy, balance by thermal conduction in the electron gas. The measured gas heating power is within the experimental error (factor 2) in agreement with calculations from the measured electron temperature and density under the assumption that the gas is heated by elastic electron-atom-collision only. A discussion of the energy balance for the total discharge indicates volume recombination losses of the ions which increase the density of the excited atoms and hence the energy losses by stepwise exitations.     

Der Einfluss von Mikrosegregations-Substrukturen auf die Kritische Schubspannung und den Verfestigungskoeffizient von Zinkeinkristallen

Zusammenfassung Der Einflu\ von Mikrosegregations-Substrukturen auf das plastische Verhalten von Zinkeinkristallen entspricht den allgemeinen Erwartungen in der Weise, da\ die kritische Schubspannung mit wachsender Substrukturendichte zunimmt. Der Verfestigungskoeffizient _A nimmt hingegen mit wachsender Substrukturendichte ab. Dabei wird der Verfestigungskoeffizient vom Charakter der Substruktur viel empfindlicher beeinflu\t als die kritische Schubspannung. Es wird angenommen, da\ dieser Einflu\ durch unterschiedlichen Fremdstoffgehalt zustande kommt.

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Die Autoren danken Herrn Prof. M. Valouch, der die Durchführung dieser Arbeit ermöglicht hat. Herrn P. Kratochvíl sei an dieser Stelle für zahlreiche Diskussionen aufs herzlichste gedankt.