Disorientation and disalignment cross sections of excited Rb-atoms colliding with noble gases

The disorientation and disalignment cross sections for the depolarization of Rb 5²P_1/2 and 5²P_3/2 states due to collisions with the inert gases He, Ne, Ar, Kr, Xe were measured at a temperature of 317 K. The experiments were done in a static magnetic field H₀ which served to decouple the nuclear spin. Unpolarized Rb-D₂-radiation was made incident on the Rb-vapour parallel to H₀ thus generating an alignment in the²P_3/2-state. The linear polarization of the fluorescent D₂-light emitted at right angles towards the incident light beam was measured as a function of the rare gas pressure (0... 3 Torr). Similarly, for the disorientation measurements the vapour was excited by circularly polarized D₂- or D₁-radiation parallel to H₀ and circularly polarized fluorescent light was observed at small angles towards the backward direction. From the decrease of the polarizations observed at rising pressure the cross sections were determined. The comparison with theoretical results gives satisfactory agreement.     

Fragmentation dynamics of ammonia cluster ions after single photon ionisation

A reflecting time of flight mass spectrometer (RETOF) is used to study unimolecular and collision induced fragmentation of ammonia cluster ions. Synchrotron radiation from the BESSY electron storage ring is used in a range of photon energies from 9.08 up to 17.7 eV for single photon ionisation of neutral clusters in a supersonic beam. The threshold photoelectron photoion coincidence technique (TPEPICO) is used to define the energy initially deposited into the cluster ions. Metastable unimolecular decay (µs range) is studied using the RETOF's capacity for energy analysis. Under collision free conditions the by far most prominent metastable process is the evaporation of one neutral NH₃ monomer from protonated clusters (NH₃) _{n ? 2}NH ₄ ⁺ . Abundance of homogeneous vs. protonated cluster ions and of metastable fragments are reported as a function of photon energy and cluster size up ton=10.     

Temperature dependence of the disorientation cross section σ 1 2/(1) in rubidium-rare gas collisions

The cross sections for the collision induced transfer²P_1/2m_j=1/2 → m_j = ?1/2 optically polarized Rb-vapour has been measured for collisions with He, Kr and Xe in the temperature range 30 °C → ～ 400 °C. The measurements were done by observing the degree of polarization in the fluorescent light emitted by the Rb-vapour. To avoid hyperfine structure effects, the nuclear spin was decoupled with a magnetic field. Calculations are presented in the temperature range 20 K → 1000 K using a semiclassical treatment and the Pascale Vandeplanque potentials. In the case of helium theoretical and experimental results are at variance, whereas for krypton and xenon satisfactory agreement is obtained. For the heavy rare gases the importance of trajectory effects, notably orbiting, becomes apparent.     

Nuclear magnetic resonance of K2 in optically pumped potassium vapor

Nuclear spin polarization in diatomic potassium molecules is produced by polarization transfer between dimers and optically pumped potassium atoms. NMR signals from K₂-molecules have been measured. Linewidth studies give information on relaxation processes of nuclear magnetic polarization.     

Zu dem Integralsatz von Cauchy

Ohne Zusammenfassung     

Zur Theorie der Differentialgleichungen

Ohne ZusammenfassungTübingen, 10. 7. 1927     

Über die Begründung der Mengenlehre

Ohne ZusammenfassungVorgetragen am 18. Sept. 1933 bei der Deutschen Mathematikertagung in Würzburg.     

Abhängigkeit von Funktionen und Rang der Funktionalmatrix

Ohne Zusammenfassung     

Über die Zerfällung rationaler Zahlen in rationale Polynomwerte

Ohne Zusammenfassung