1,721,031 research outputs found
Temperature dependence of low-energy radiation damage
No full textThe creation of Frenkel pairs by low-energy radiation has been simulated at zero and room temperature. The radiation of Frenkel pairs is shorter at higher temperature. This diminution is partially due to a restoring capacity of the crystal
Effect of thermal vibration on low-energy collision cascades
No full textUsing computer simulation, collision sequences of energy up to 100 eV been studied in Cu at zero and room temp. The effect of correlated thermal vibration and zero point motion on the length of focused collision sequences, on the energy loss per collision, and on the radius of created Frenkel pairs has been evaluated. Collision sequences along close-packed atomic rows are found to exist for recoil energies well above the focusing energy; however, the length of the sequences is reduced by thermal vibration and zero point motion. A semi-empirical law which relates the energy loss per collision direction with energy and temperature has been derived. Experimental results on the production of Frenkel pairs are discussed. 13 re
Formation of Frenkel pairs in electron irradiated copper
No full textA computer simulation was performed to study the creation of Frenkel pairs in electron-irradiated Cu at O and 293 deg K. The average radius of Frenkel pairs was calculated as a function of the recoil energy of the knock-on atom out from this, the mean radius of Frenkel pairs created by electron irradiation of given energy was calculated. At the end of focused collision sequence which generates the interstitial, the local transient heating produces defect jumps which slightly reduce the mean radius of the Frenkel pairs. The direction of these jumps allows an approximate determination to be made of the vacancy--interstitial attraction range, which is compared with experimental data for the recombination radius. 13 ref
Local equilibrium in stationary states by molecular dynamics
No full textI have further developed a molecular-dynamics technique, based on the introduction of stochastic boundary conditions, which had been used previously to simulate stationary nonequilibrium states. By simulating two symmetrical thermal gradients, periodic boundary conditions can be used in all directions. In this way unphysical effects of the thermal walls, existing in the previous version of the technique, have been eliminated. The local equilibrium hypothesis has been verified throughout the whole region of the thermal gradient. The new technique seems suited to study the correlation of dynamical variables in stationary nonequilibrium states. 10.1103/PhysRevA.28.313
Self-trapping of infrared energy absorbed in acetanilide
No full textAcetanilide (ACN) has an anomalous low temperature IR absorption band, which has been attributed to a self-trapped state of molecular vibrational energy in the amide group (Davydov-like soliton). A classical model for a segment of an ACN chain has been set up, taking into account the degrees of freedom of the amide group involved in the H-bond: stretching of C=O bond, stretching and bending of the H-bond. The dynamics of the molecule has been investigated by molecular dynamics simulation
Classical specific heat of an atomic lattice at low temperature, revisited (vol 57, pg 100, 1998)
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