Electron drift mobility in amorphous semiconductor multilayer superlattices

It is proposed that the X-ray intensity I at the forbidden 222 reflection is useful as an order parameter in the phase transition from a diamond-lattice semiconductor to a metal. Available X-ray data as a function of pressure on Si is shown to lend some support to the proposal.     

Quantitative NRA and SIMS depth profiling of hydrogen in naturally weathered medieval glass

Summary NRA and SIMS measurements were carried out with samples from naturally weathered medieval glass paintings in order to study the quantitative depth distribution of hydrogen in the surface layers. The major parts of the profiles show good agreements in shape and depth. Nevertheless, differences were observed in the near-surface region. It could be shown that proper attention has to be paid to the vacuum environment of the instruments and to sample preparation before evacuation in order to avoid evaporation of hydrogen containing species incorporated into the silicate structure during leaching or weathering.

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Quantitative NRA- und SIMS-Tiefenprofilanalyse von Wasserstoff in natürlich verwitterten mittelalterlichen GlÄsern

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Dedicated to Prof. Dr. Wilhelm Fresenius with sincere appreciation on the occasion of his 75th birthday     

Overlap of He atom and He+ ground-state wave functions and calculation of ionization potential

The one-body equation proposed earlier for determining the overlap of He atom and He⁺ wave functions can be given a fundamental justification. This equation with an approximate form of one-body potential can be solved, and an excellent ionization potential results. The helium atom ground-state wave function can thereby be refined.     

Kinetic energy change due to interaction between charged centres in metals and its relation to that occurring in covalent bond formation

A proposal has recently been made to represent the kinetic energy change ΔT(R) in a diatomic molecule over the entire range of internuclear separation R. The same representation is useful for charged centres interacting in a degenerate Fermi gas.     

Monolayer structure for some dissociatively adsorbed molecules and molecular H2O on noble and transition metal surfaces

The model of neighbour site blockage for atomic adsorption on noble and transition metal surfaces predicts monolayer structures quite successfully. For molecularly adsorbed water, the assumption that the molecular separation in the monolayer is that in the basal plane of bulk I_h ice predicts the majority of known monolayer structures.     

Liquid metal pair potentials from structure data

In linear screening theory, the zeroth order result is the equality of the potential of mean force and the pair potential. The Kirkwood superposition approximation holds to the same order.The next order yields an equation for the pair potential identical with the first order iteration of Johnson and March from the Born-Green equation.     

Model results for π electrons in polyenes

The Lieb-Wu exact solution of the Hubbard-Gutzwiller hamiltonian in one dimension is examined numerically, because of its potential interest for π electrons in polyenes. The band gap introduced by electron correlation is small even when the electron-electron interaction energy is equal to the band width.     

Topology of fermi surface and the calculation of the phase diagram of lithium by variable cell molecular dynamics

In connection with the study of the phase diagram of metallic lithium, carried out by molecular dynamics using a cell of variable shape and size, it is pointed out that the topology of the Fermi surface is drastically altered in going from body-centred cubic through body-centred tetragonal to face-centred cubic. This is evidenced both by Korringa-Kohn-Rostoker band structure calculations and by high pressure electrical resistivity measurements of Li through a phase transition.     

Ligand exchange and solvolytic reactions of99mTcBr 6 2− in non-aqueous media

Prior work had documented that^99mTcCl ₆ ^2– could undergo ready ligand exchange reaction under non-aqueous condition. We now wish to report the ligand exchange reaction of bromine in^99mTcBr ₆ ^2– in non-aqueous solvents using 8-hydroxyquinoline (oxine) as the displacing ligand. Analysis of the products obtained by paper chromatography, HPLC and electrophoresis suggest that a 12 Tcoxine complex appears to be the most stable of the complexes formed, probably^99mTc(oxine)₂ Br₂. However, displacement of bromine by polar solvents (both protic and aprotic) can also occur, both on^99mTcBr ₆ ^2– and in the above complex as a consequence of solvolytic reactions. Other Tc-oxine complexes can also be formed upon ligand exchange, but they appear to be stable only under aprotic, non solvolytic conditions. These studies again document that hexahalotechnetate complexes exhibit ligand exchange reactions under non-aqueous conditions, that they allow the ready synthesis of novel technetium complexes, but that because of their high reactivity the effect of competing reactions must be considered.