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Silicide formation at the Ti/Si(111) interface J. Vac. Sci.

It is noted in this paper that the total energy of the electron-ion system in the metallic state arises from an electron self-energy term as well as volume-dependent pairwise interaction terms among the ions. The Slutsky-Garland model used by Schmunk et al. to analyze the experimental dispersion curves of Be does not give the proper elastic behavior. The experimental dispersion curves for beryllium and zinc measured by Schmunk et al. and Borgonovi et al., respectively, are analyzed using a model consistent with the elastic behavior. For beryllium, the calculated dispersion curves agree well with the neutron inelastic-scattering data and the elastic constants of Smith and Arbogast. For zinc, the calculated frequencies are within the experimental uncertainties with the exception of the transverse branches along the [OllO] direction which describes atomic motions perpendicular to the basal planes. The experimental data on Zn indicate high dispersion and fluctuations in frequency w versus wave number q. The calculated elastic constants agree within a few percent with the experimental data of Alers and Neighbours at 300°K, with the exception of C44 and C13, which are low by 19% and 27%, respectively. The Debye-Waller factor and the specific heat for both metals are compared with available experimental data. It is found that the calculated specific heat for zinc is in excellent agreement with experiment over the whole temperature range. However, for beryllium, the calculated values are low for small temperatures; the discrepancy could be attributed to heavy impurities in beryllium. The anisotropy in the Debye-Waller factor for zinc is in good agreement with x-ray and Mossbauer experiments.

Measurements have been made of relative marker movements in Au and Cu in the presence of temperature gradients of the order of 1200°K/cm. These experiments yielded results which indicate that a net vacancy current is established in these metals under appropriate experimental conditions. The magnitude and direction of the observed effects are consistent with kinetic theory predictions in conjunction with previously determined vacancy energies. A three-dimensional extension of existing kinetic theory is developed and important factors which do not appear in one-dimensional treatments are discussed. Porosity development in Cu was found under certain conditions and this may be a visual demonstration of the existence of a thermal diffusion effect in Cu.

A new analysis is presented of the shape of a liquid drop under the influence of gravity and surface tension. A variational method is used to minimize the total energy of the drop and the resulting expressions for the drop shape are evaluated numerically. The new treatment makes more direct use of the accurately measurable drop width than do the classical treatments based on the analysis of Bashforth and Adams.