Otto Stern (1888-1969): The founding father of experimental atomic physics

We review the work and life of Otto Stern who developed the molecular beam technique and with its aid laid the foundations of experimental atomic physics. Among the key results of his research are: the experimental determination of the Maxwell-Boltzmann distribution of molecular velocities (1920), experimental demonstration of space quantization of angular momentum (1922), diffraction of matter waves comprised of atoms and molecules by crystals (1931) and the determination of the magnetic dipole moments of the proton and deuteron (1933).Comment: 39 pages, 8 figure

Modeling of stress-strain state of cement-sand grouting on foundation deformation

The application of jet grouting has been becoming more widespread in the reinforcement of building foundations. This technique depends on the characteristic features of the foundation soil, relevant type of foundation and surrounding conditions. The numerical analysis was carried out with three typical load intensities, proving that the intensity of the foundation settlement being influenced by the growth of soil stiffness and strength. The calculation of vertical soil displacements is 7.9 mm before underpinning, while it is 6.5 mm after underpinning. It is defined that the use of jet structures to strengthen the ground base allows to increase the rigidity of the base and to reduce its vertical movement by 20%. The hypothetical displacements were identified of the base by varying of its mechanical properties to the optimal values

Abrupt Rise of the Longitudinal Recoil Ion Momentum Distribution for Ionizing Collisions

We report on the experimental observation of an abrupt rise in the longitudinal momentum distribution of recoil ions created in proton helium collision. The details of this structure can be related to electrons traveling with the velocity of the projectile [electron capture to the continuum (ECC)]. The longitudinal as well as the transverse distribution of the recoil ions can be explained as a continuation of the momentum distribution from ions resulting from electron capture illustrating the smooth transition from the capture to bound states of the projectile to the ECC.Fil: Weber, Th.. Institut für Kernphysik; AlemaniaFil: Khayyat, Kh.. Institut für Kernphysik; AlemaniaFil: Dörner, R.. Universität Freiburg; AlemaniaFil: Rodríguez Chariarse, Vladimir Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Mergel, V.. Institut für Kernphysik; AlemaniaFil: Jagutzk, O.. Institut für Kernphysik; AlemaniaFil: Schmidt, L.. Institut für Kernphysik,; AlemaniaFil: Müller, K. A.. Institut für Kernphysik; AlemaniaFil: Afaneh, F.. Institut für Kernphysik; AlemaniaFil: Gonzalez, A.. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Schmidt-Böcking, H.. Institut für Kernphysik; Alemani

Homogeneous Catalyst Recycling and Separation of a Multicomponent Mixture Using Organic Solvent Nanofiltration

In homogeneous catalysis, the application of organic solvent nanofiltration (OSN) has become a well-known alternative to common recycling methods. Even though some OSN membranes are commercially available, their classification and the scope of application have to be determined for the specific solvent mixture. The commercial membrane Evoniks DuraMem® 300 was tested in a mixture of ethanol, ethyl acetate, and cyclohexane with magnesium triflate as possible catalyst. The cross permeate fluxes were measured for two transmembrane pressures and the hydrodynamic radii of the components were determined. Some of the components in the ternary mixture are retained, which makes the membrane also suitable for fractioning thereof. © 2019 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei

Recoil-Ion and Electron Momentum Spectroscopy: Reaction-Microscopes

Recoil-ion and electron momentum spectroscopy is a rapidly developing technique that allows one to measure the vector momenta of several ions and electrons resulting from atomic or molecular fragmentation. In a unique combination, large solid angles close to 4 and superior momentum resolutions around a few per cent of an atomic unit (a.u.) are typically reached in state-of-the art machines, so-called reaction-microscopes. Evolving from recoil-ion and cold target recoil-ion momentum spectroscopy (COLTRIMS), reaction-microscopes—the `bubble chambers of atomic physics'—mark the decisive step forward to investigate many-particle quantum-dynamics occurring when atomic and molecular systems or even surfaces and solids are exposed to time-dependent external electromagnetic fields. This paper concentrates on just these latest technical developments and on at least four new classes of fragmentation experiments that have emerged within about the last five years. First, multi-dimensional images in momentum space brought unprecedented information on the dynamics of single-photon induced fragmentation of fixed-in-space molecules and on their structure. Second, a break-through in the investigation of high-intensity short-pulse laser induced fragmentation of atoms and molecules has been achieved by using reaction-microscopes. Third, for electron and ion-impact, the investigation of two-electron reactions has matured to a state such that the first fully differential cross sections (FDCSs) are reported. Fourth, comprehensive sets of FDCSs for single ionization of atoms by ion-impact, the most basic atomic fragmentation reaction, brought new insight, a couple of surprises and unexpected challenges to theory at keV to GeV collision energies. In addition, a brief summary on the kinematics is provided at the beginning. Finally, the rich future potential of the method is briefly envisaged

Design Studies of an Electrostatic Storage Ring

Electrostatic storage rings combine a number of very interesting characteristics that make them an attractive tool in the low energy range. In contrast to magnetic rings, all of the fields in an electrostatic storage ring are completely mass independent. At the same particle energy and charge state, ions from light protons to heavy biomolecules can in principal be stored with identical field setups. A small ring for ions of energies up to 50 keV is planned to be built up at Goethe University in Frankfurt. Different designs have been calculated and the results are presented in this contribution. Furthermore, prototypes of the necessary optical elements have been manufactured and are described as well