Tae spin-lattice relaxation of deuterated methyl groups, which is exponential at high temperatures, becomes non-exponential at low temperatures as evidence of the coupling between the Zeeman and tunneling systems. The dominant relaxation is considered to be the quadrupole interaction. Experimental results at liquid nitrogen and liquid helium temperatures support the theoretical model.

In Part I the kinetic theory of excitations in flowing liquid He II is deve loped to a higher order than that carried out previously, by Landau and Khalatnikov, in order to demonstrate the existence of nonequilibrium terms of a new nature in the hydrodynamic equations. It is then shown that these terrns can lead to spontaneous destabilization in counter currents when the relative velocity of th...

The stability of multielectron bubbles (MEBs) in liquid helium is investigated using the liquid-drop model for fissioning nuclei. Whereas a critical positive pressure can make the bubble unstable against fissioning, a small negative pressure suffices to introduce a restoring force preventing any small deformation of the bubble to grow. We also find that there exists an energy barrier making MEB...

für Naturforschung in cooperation with the Max Planck Society for the Advancement of Science under a Creative Commons Attribution 4.0 International License. Dieses Werk wurde im Jahr 2013 vom Verlag Zeitschrift für Naturforschung in Zusammenarbeit mit der Max-Planck-Gesellschaft zur Förderung der Wissenschaften e.V. digitalisiert und unter folgender Lizenz veröffentlicht: Creative Commons Namen...

of a bubble (F is the diele~tric onstant of liquid helium) gives the class~cal *'Coulomb radius" of the bubble (this value is accurate for the bubbles considered ( 5 , 6)). For typical charges Z of 10510' electrons, this yields radii between 10 and 100 pm. The electrons in a bubble are confined to a narrow region of only a fcw Bngstrorns width close to the bubble surface, owing to their mutual ...

An experimental approach is presented that allows for the incorporation of large mass-to-charge ratio selected ions in liquid helium droplets. It is demonstrated that droplets can be efficiently doped with a mass-to-charge ratio selected amino acid as well as with the much bigger m ≈ 12,000 amu protein cytochrome C in selected charge states. The sizes of the ion-doped droplets are determined vi...

The capability of charcoal as a sorbent for helium at cryogenic temperatures depends upon charcoal characteristics that are not well understood. Previous work by the authors has indicated that the charcoals' pumping capability for helium depends as much on their source as on their particle size distributions. To develop a correlation between the physical characteristics of charcoal and helium p...

ALTHOUGH the birth of the universe is inaccessible to human experimental investigation, aspects of cosmological theories can nonetheless be explored in the laboratory. Tiny inhomogeneities in the mix of particles and radiation produced in the Big Bang grew into the clusters of galaxies that we see today, but how those inhomogeneities arose and grew is still unclear. Cosmologies based on grand u...