Electronic band structure of calcium oxide

We employed electron momentum spectroscopy (EMS) to measure the bulk electronic structure of calcium oxide. We extracted the electron momentum density (EMD), density of occupied states (DOS), band dispersions, bandwidths and intervalence bandgaps from the data. The results are compared with calculations based on the full potential linear muffin-tin orbital(FP-LMTO) approximation. While the bandwidths of 0.6±0.2 and 1.2±0.1 eV for the s- and p-bands, respectively, and their dispersions agree well with the LMTO calculation, the relative intensity of the two bands is at odds with the theory. The measured intervalence bandgap at the Γ-point of 16.5±0.2 eV is larger by 2.1 eV than that from the LMTO calculation. The experimental bandwidth of the Ca 3p semi-core level of 0.7±0.1 eV agrees with the LMTO prediction. The measured bandgap between this level and the s-band is 3.6±0.2 eV. The Ca 3s-3p level splitting is in excellent agreement with the literature. © 2004 Elsevier B.V. All rights reserved

Electronic band structure of beryllium oxide

Atomic and Molecular Physics Laboratories, Research School of Physical Sciences and Engineering, The Australian National University, Canberra ACT 0200, Australia. The energy-momentum resolved valence band structure of beryllium oxide has been measured by electron momentum spectroscopy (EMS). Band dispersions, bandwidths and intervalence bandgap, electron momentum density (EMD) and density of occupied states have been extracted from the EMS data. The experimental results are compared with band structure calculations performed within the full potential linear muffin-tin orbital approximation. Our experimental bandwidths of 2.1 ± 0.2 and 4.8 ± 0.3 eV for the oxygen s and p bands, respectively, are in accord with theoretical predictions, as is the s-band EMD after background subtraction. Contrary to the calculations, however, the measured p-band EMD shows large intensity at the Γ point. The measured full valence bandwidth of 19.4 ± 0.3 eV is at least 1.4 eV larger than the theory. The experiment also finds a significantly higher value for the p-to-s-band EMD ratio in a broad momentum range compared to the theory

Monte Carlo-based modeling of secondary particle tracks generated by intermediate- and low-energy protons in water

This chapter gives an overview of recent developments in the Monte Carlo-based modeling of the interaction of ionizing radiation with biologically relevant systems. Several track structure codes, such as Geant4 (GEometry ANd Tracking 4), Geant4-DNA, and LEPTS (Low-Energy Particle Track Simulation), are described. Main features, areas of application and current limitations of each tool are discussed. A special attention is focused on the energy range covered by primary and secondary charged particles and on the type of interactions included in the simulation. A recent development of LEPTS is presented, aimed at the simulation of full slowing-down of protons in water together with all molecular processes involving secondary particles. The utilized approach allows one to study radiation effects on the nanoscale in terms of the number and the type of induced molecular processes