A. I. Dodonov

Directional effects of the molecular ion reflection from a crystal surface

Abstract The reflection of 30 keV molecular N+2 ions from the (100) face of copper crystal has been studied experimentally. Under the examined experimental conditions, the yield of the reflected molecular ions has been found to sharply increase when the primary ion incidence plane gets parallel to the axis of the surface semichannels formed by the close-packed atomic rows of a single-crystal target. The magnitude of the effect is more than 15 times as high compared with random orientation of the primary beam with respect to the irradiated crystal target.

The features of molecular ion dissociation for ion reflection from a copper single-crystal surface

Reflection of 30 keV molecular nitrogen ions from a (100) copper crystal face is studied for a variety of experimental geometries. The dependence of the ion intensity on the azimuthal angle of target rotation throughout the variation interval of glancing angles studied is much stronger for molecular ions reflected without dissociation compared with the dissociated ions.

Effect of surface semichanneling on energy distributions of molecular ions reflected from single-crystal surface

Abstract Regularities in the energy distributions of molecular nitrogen ions reflected from (100)Cu crystal face are studied. The half-widths (FWHM) of the energy distributions of the reflected ions have been found to vary strongly near aligned orientations of the target with respect to the bombarding ion beam. A relationship has been found between the survival fraction of reflected molecular ions and the effect of ion focusing in surface semichanneling.

Experimental and Computer Study of the Spatial Distributions of Particles Sputtered from Polycrystals

The spatial distributions of the sputtered particles were simultaneously and separately studied by experiment and computer simulation for 30 keV argon ion bombardment of copper in a wide range of primary-ion incidence angles (0°–86°). The distributions were found to be similar. The discrepancies between the data obtained and the predictions of the Roosendaal-Sanders analytical theory are discussed.

Directional effects in the reflection of molecular ions with energies of tens of kev from crystal surface

Abstract The regularities of reflection of molecular nitrogen ions with a 30 keV initial energy from the (100) Cu crystal face have been studied experimentally. The ion fraction reflected without dissociation has been found to be a nonmonotonic function of crystallographic direction. The results obtained are discussed in terms of a two-atom model.

Temperature effects in fast recoils ejection

Abstract The detailed dependences of the parameters of fast ionized recoil flux ejected from both single- and polycrystalline copper targets under 30 keV Ar ion bombardment on experimental geometry and target temperature have been obtained. It has been found that the target temperature may strongly affect the fast-recoil ejection from the single-crystal target. The strongest temperature effects take place in the case of aligned target orientation. The effect of the geometric factors of the experiment diminishes with rising target temperature, so that the parameters of the recoil flux at sufficiently high temperatures for a single-crystal target become the same as in case of a polycrystal target. The effect of thermal vibrations of lattice atoms on the process of fast-recoil ejection is analyzed in terms of the model of a vibrating isolated atomic row. The method is described in detail for calculating the energy distributions of the ejected atoms with due account of the correlation of thermal displacements...

Effect of surface semichannels in fast recoil energy distributions

Abstract Directional effects in the energy distributions of fast ionized recoils ejected from copper under 30 keV energy argon ion bombardment were studied. As targets single crystal faces with different mutual arrangements of close-packed atomic rows and also a copper polycrystal were used. It was found that at aligned target orientation the energy distributions are much broader than for both random target orientation and for the polycrystalline target. It was also found that the energy distributions are affected by the mutual arrangement of close-packed atomic rows. The obtained results are discussed in terms of vibrating atomic rows.

Spatial distribution of sputtered particles from polycrystals under ion bombardment

Abstract The spatial distributions of sputtered particles for the 30 keV Ar+-Cu combination are studied experimentally by the collector method. The angle of ion incidence onto a target is varied within a broad interval from 0 to to 86° relative to a target surface normal with a 2–5° step. The transition from the conventional cascade ejection to the ejection influenced strongly by primary knock-ons has been traced in detail.

Energy and spatial redistributions of the particle flux resulting from its interaction with the scattering center

Energy and intensity distributions of both projectiles and recoil atoms on the plane behind the scattering center at finite distance are calculated for different projectile-to-target mass ratio and different projectile energies. The projectile energy and intensity have been found to be double-valued or three-valued functions of the distance from the collision epicenter. At the same time, the recoil energy and intensity have proved to single-valued and double-valued functions of the distance from the collision epicenter for parallel and divergent projectile fluxes, respectively.

The effect of thermal vibrations of crystal lattice on the energy distributions of fast ionized recoils

Abstract The effect of target temperature on the energy distribution of fast ionized recoils produced during 30 keV Ar ion bombardment of the Cu(110) face has been studied experimentally. Both the shape of the distribution and the energy position of the distribution maximum have been found to vary with rising temperature. The results obtained are discussed in terms of the vibrating isolated atomic row model.