Optical absorption spectra of Xene and Xane (Xsilic, german, stan).

We study optical absorption spectra of Xene and Xane (X = silic, german, stan). The results show that the optical absorption spectra of Xenes are dominated by a sharp peak near the origin due to direct interband transitions near thepoint of the Brillouin zone. Meanwhile, the optical absorption spectra of Xanes are characterized by an excitonic peak.

Optical absorption and excitation spectra of monolayer blue phosphorene.

We study the optical absorption and excitation spectra of monolayer blue phosphorene with two approaches. The first is based on the [Formula: see text] approximation in conjunction with the Bethe-Salpeter equation theory. The second is based on the time-dependent density-functional theory in the adiabatic local density approximation and the random phase approximation.

Electron elastic backscattering probability and inelastic mean free path.

We study the angular distribution of electron elastic backscattering probability, using the Oswald-Kasper-Gaukler (OKG) model and Monte Carlo simulation. The present results are consistent with experimental data and other theoretical calculations. We also propose an approach that makes the OKG model applicable to determine electron inelastic mean free paths for compounds.

Low-energy electron inelastic mean free paths for liquid water.

We improve the Mermin-Penn algorithm (MPA) for determining the energy loss function (ELF) within the dielectric formalism. The present algorithm is applicable not only to real metals, but also to materials that have an energy gap in the excitation spectrum. Applying the improved MPA to liquid water, we show that the present algorithm is able to address the ELF overestimation at the energy gap, and the calculated results are in good agreement with experimental data.

Electron inelastic mean free path at energies below 100 eV.

Knowledge of electron inelastic mean free paths (IMFPs) is important for electron spectroscopy and microscopy studies. Here, we determine the IMFPs at energies below 100 eV for 10 elemental solids (V, Fe, Ni, Mo, Pd, Ag, Ta, W, Pt, and Au) within the dielectric formalism, using the energy-loss function calculated in the adiabatic local-density approximation of time-dependent density-functional theory. The resulting IMFPs at a few eV above the Fermi energy are comparable to those from ab initio calculations in the GW approximation of many-body theory.

Modified Bethe formula for low-energy electron stopping power without fitting parameters.

We propose a modified Bethe formula for low-energy electron stopping power without fitting parameters for a wide range of elements and compounds. This formula maintains the generality of the Bethe formula and gives reasonable agreement in comparing the predicted stopping powers for 15 elements and 6 compounds with the experimental data and those calculated within dielectric theory including the exchange effect. Use of the stopping power obtained from this formula for hydrogen silsesquioxane in Monte Carlo simulation gives the energy deposition distribution in consistent with the experimental data.