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A useful method of calculating the energy/unit depth deposited in atomic processes by energetic ions in solids is presented. The calculated energy density is shown to correlate well with previous Monte Carlo calculations of the vacancy concentration resulting from ion bombardment and recent experimental measurements of the depth distribution of ion damage. The method also provides the depth distribution of ions in the solid as a function of their energy during the stopping process. This information would allow, for example, calculation of the location and rate of various energy‐dependent interactions between incident ions and host atoms.

The correct prediction of the electronic stopping power is important in establishing the basis for the technique of ion bombardment of neutron damage. Experimental measurements of the stopping power and the depth distribution of damage deposition by heavy atomic projectiles incident on matter have shown that the velocity proportional electronic stopping power formulas of Lindhard and Firsov are not valid for projectile velocities in the range from 2v0 up to v1, where v0 is the Bohr velocity and v1 is Lindhard’s proposed upper limit for the validity of these formulas. This letter points out that a previously published modification of the Firsov theory predicts a strong superlinear dependence of the stopping power on velocity in this velocity region due to effects which arise when the incident projectile velocity is comparable with that of the atomic electrons. Apart from a scale factor along the velocity axis, which must be determined from experimental measurement, the modified theory correctly predicts th...

The lasing transition in bulk Zn‐doped GaAs has been resolved into three components (A′, B′, C′) with energies at 1.504, 1.489, and 1.484 eV, respectively. The higher energy levels are depopulated at low temperatures. The temperature dependence of the intensity of the transitions indicates a single luminescent center with a ground state and three excited states. A group‐theoretical analysis based on the Td symmetry of the Zn acceptor with s1/2 conduction band electrons and p3/2 valence band holes leads to the conclusion that the luminescent center must have lower symmetry than Td. The various possible types of centers are mentioned but there are no a priori reasons for choosing one over the other at the present time.