We studied threshold displacement energies for creating stable Frenkel pairs in silicon using density functional theory molecular dynamics simulations. The average threshold energy over all lattice directions was found to be $36\pm 2_{\text{ST}\text{AT}}\pm 2_{\text{SY}\text{ST}}\text{eV}$, and thresholds in the directions $⟨100⟩$ and $⟨111⟩$ were found to be $20\pm 2_{\text{SY}\text{ST}}\text{eV}$ and $12.5\pm {1.5}_{\text{SY}\text{ST}}\text{eV}$, respectively. Moreover, we found that in most studied lattice directions, a bond defect complex is formed with a lower threshold than a Frenkel pair. The average threshold energy for producing either a bond defect or a Frenkel pair was found to be $24\pm 1_{\text{ST}\text{AT}}\pm 2_{\text{SY}\text{ST}}\text{eV}$.

The distributions of H atoms, displaced Si atoms, and vacancy-type defects in Si(100) produced by the implantation, at room temperature, of 1×${10}^{16}$ 35-, 60-, and 100-keV ${\mathrm{H}}^{+}$-ions/${\mathrm{cm}}^2$ were measured with use of ion and slow-positron beam techniques. Three different regions of damage were observed. The damage distribution did not correlate with the deposited energy distribution. A vacancy-type damage region surviving room-temperature annealing and the dynamic annealing during implantation is produced in the region where the energy of the primary Si recoils exceeds a threshold value of 2.0±0.5 keV, i.e., an energy spike is needed for damage formation. In the region of the deposited energy peak, H is associated with damage consisting of SiH centers and vacancy complexes. At the end region of the implantation range, the distribution of displaced Si atoms is produced by H impurities in crystalline Si. Two different recovery stages were observed. The first stage, at 500 K, is associated with the damage region containing vacancy-type defects and SiH centers with vacancy complexes; the recovery energy is 1.7 eV. The second stage, at 700 K, is attributed to the end region of the H range, where the recovery energy associated with the recrystallization of Si after the H loss is 2.1 eV.

A reactive interatomic bond-order potential for bcc tungsten is presented. Special attention in the potential development was given for obtaining accurate formation and migration energies for point defects, making the potential useful in atomic scale simulations of point and extended defects. The potential was used to calculate binding energies and trapping distances for vacancies in vacancy clusters and the recombination radius for self-interstitial atom and monovacancy.