Remarks on stopping power: Its connections with particle transport and with the electronic structure of matter

This article presents remarks on the meaning of stopping power and of its magnitude. More precisely, the first set of remarks concerns the connection of stopping power with elements of particle-transport theory, which describes particle transport and its consequences in full detail, including its stochastic aspects. The second set of remarks concerns the magnitude of the stopping power of a material and its relation with the material's electronic structure and other properties. © 1996 John Wiley & Sons, Inc.     

Hydrogen-like relativistic corrections for electric and magnetic hyperfine integrals

Expressions are derived for the n-dependent, hydrogen-like relativistic corrections to the magnetic dipole and electric quadrupole radial hyperfine integrals of an arbitrary atomic state. Good agreement has been obtained earlier between these corrections and the relativistic Hartree-Fock results for s_1/2 states. The agreement remains good for the p_1/2 states. For the p_3/2 states in heavier atoms the hydrogenic corrections still reproduce the Hartree-Fock trend. For the higher l values the agreement is poor. Numerical tables are given for 1 ≤ Z ≤ 100 for the s_1/2, p_1/2, and p_3/2 magnetic dipole cases and the p_3/2 quadrupole case.     

Cauchy's dispersion equation reconsidered: Dispersion in silicate glasses

We formulate a novel method of characterizing optically transparent substances using dispersion theory. The refractive index is given by a generalized Cauchy dispersion equation with coefficients that are moments of the uv and ir absorptions. Mean dispersion, Abbé number, and partial dispersion are combinations of these moments. The empirical relation between index and dispersion for families of glasses appears as a consequence of Beer's law applied to the uv spectra.     

Triple ionization of lithium by electron impact

Ejection of the three electrons from lithium in a single electron collision has been observed for the first time. Triply charged lithium was observed in an ion time-of-flight spectrum following electron impact on a sample of ultracold, trapped lithium. The higher signal/background afforded by the trap environment made the observation of Li3+ possible. We measured the ratios of triple-to-double and double-to-single ionization at an impact energy of 1000 eV. The 3+/2+ ratio is approximately 0.001, a value 2 orders of magnitude lower than semiempirical predictions. We present a simple method that uses photoionization data combined with sum-rule analysis to predict the asymptotic charge-state ratios. The sum-rule predictions compare reasonably with experiment and shake calculations, but disagree sharply with the semiempirical estimates.     

Strong completeness of lattice-valued logic

 Strong completeness of S. Titani's system for lattice valued logic is shown by means of Dedekind cuts. Received: 26 June 2000 / Published online: 31 May 2002     

Proof theory for minimal quantum logic: A remark

It is remarked that the inference rule ( ) is superfluous for the sequential system GMQL introduced by H. Nishimura for the minimal quantum logic.     

VUV absorption and its relation to the effects of ionizing corpuscular radiation

Elements of the physics of photoabsorption as well as of energy transfer from fast charged particles are discussed. Among the key notions there are oscillator-strength spectra, quantum yields, and action spectra. Throughout the discussion, emphasis is put on the important role of soft X-rays and VUV light as obtained from a synchrotron radiation source in the understanding of actions of ionizing radiations in general.     

Search for low-lying resonances in electron scattering by atomic hydrogen

Measurements of the transmission of an energy-selected electron beam through atomic hydrogen fail to indicate any resonance below 9·5-eV electron energy. The negative result contradicts recent suggestions by Rudkjøbing and by Van Rensbergenthat some diffuse interstellar absorption bands might be attributable to preionizing transitions in the hydrogen negative ion. A bulk of reliable theoretical data, however, justifies our finding.