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No abstract available

[en] In this review, the author discusses some recent developments in one area of atomic collisions, namely the scattering of atoms, ions and molecules on each other in the range of energies from subthermal to about 10eV. The major motivation for these experiments is the determination of the intermolecular potential. Actually there are two types of potentials, the 'chemical' potential involving strong attractive exchange forces which hold molecules together as in H₂¹Σ and the much weaker but equally important van der Waals potentials involving weakly attractive London correlation forces such as in He-He or H₂³Σ. (Auth.)

[en] A review is presented of the conversion of translational into internal rotational and vibrational energy given by: A + BC(j/sub i/, m/sub i/, n/sub i/) → A + BC(j/sub f/, m/sub f/, n/sub f/) +- ΔE where A is a ground state atom, another molecule--considered to be structureless--or an ion, and BC is usually a diatomic molecule with rotational quantum states j and m and vibrational state n; i and f denote initial and final states, respectively, and ΔE denotes the change in relative translational energy. 4 figures, 4 tables, 341 references

[en] Experimental progress in molecular physics is illustrated with emphasis being placed on the study of interactions in three-body and many-body systems. The results are presented of four experiments using the experimental technique of time-of-flight energy loss spectroscopy of atomic or molecular particles at interactions. The experiments are in principle analogous with scattering experiments in nuclear physics. The elastic and inelastic scattering was measured of 20 meV ⁴He atoms by molecules of N₂, O₂, CO, CH₄, and on the surface of noble metals, of proton beams with energy ranging between 10 and 20 eV on a CH₄ molecular beam, and of HD molecules with energies of up to 30 meV on the surface of gold. Molecular spectroscopic data were obtained with high resolution such as may be compared with model calculations. (S.P.)

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[en] The scattering of molecular beams of ⁴He atoms from solid surfaces provides a very sensitive diffractive probe of surface structure and surface dynamics. The experimental method is described and illustrated by some studies of surface structure of metal surface. Because of the high monochromaticity of the helium beams (Δυ/υ ≅ 1%) surface phonons with energies from 0.5 meV upwards can be resolved and entire surface phonon dispersion curves can be measured. On Cu(111) and CU(001) an anomalous longitudinal resonance with large intensity is observed. On W(001) and W(110) + H(1 x 1) sharp anomalies give evidence of electron-phonon coupling which in the former system is related to the reconstruction at 280 K. Finally, two experiments on the dynamics of thin films as a function of layer thickness are described. (author)

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No abstract available

[en] The injection of vacancies into a solid under a strong pressure gradient can in principle be achieved in all cases where vacancy mobility is sufficiently high, e.g. close to melting or in quantum solids. The transport problem of vacancy injection from vacuum is solved in one dimension and used to analyze recent experiments for the special case of solid ⁴He. The vacancy mobility is obtained from the measurement of the velocity of a supersonic nozzle beam generated by a solid ⁴He source