Rate constant of non-adiabatic processes on a metal surface

The rate constant of non-adiabatic activated processes is expressed as k = κk_TST, where k_TST is the transition-state-theory rate constant. In the present paper the transmission coefficient, κ, is derived for the rate process limited by weak coupling of the initial electronic diabatic state with a continuum of the final diabatic states.     

Parametric interaction of surface waves guided by a plasma layer

We study the linear stage of the parametric instability of high-frequency surface waves guided by a homogeneous plasma layer on a metallic substrate when a TM-polarized plane electromagnetic wave is incident on the layer. The instability growth rate and the threshold value of the pumping wave amplitude are determined. It is shown that the instability can be thresholdless in a certain range of permittivities and thicknesses of the layer. Radiophysical Research Institute, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 40, No. 7, pp. 870–876, July, 1997.     

On the interaction of a hydrogen atom with a lithium metal surface

In this paper we adopt a molecular cluster approach to study the interaction of a hydrogen atom with a (100) surface of solid lithium metal. In this study, the spin-unrestricted Hartree-Fock equation is solved for the molecular cluster. We also solve for the potential energy surface of the LiH molecule and the Li₂ molecule. We find that the essential features of the hydrogen surface interaction can be understood in terms of the molecule two body interactions. We also find that the hydrogen atom sits below the surface of the Li metal rather than above the surface.     

Long-range repulsive interaction between molecules on a metal surface induced by charge transfer

The adsorption of a molecular electron donor on Au(111) is characterized by the spontaneous formation of a superlattice of monomers spaced several nanometers apart. The coverage-dependent molecular pair distributions obtained from scanning tunneling microscopy data reveal an intermolecular long-range repulsive potential, which decreases as the inverse of the molecular separation. Density functional theory calculations show a charge accumulation in the molecules due to electron donation into the metal. Our results suggest that electrostatic repulsion between molecules persists on the surface of a metal.     

Nonadiabatic rate processes on metal surface: Limitation by spin conversion

Rate processes occurring on a metal surface may sometimes be limited by spin conversion. We present a generic model describing this case. The results obtained are compared with the conventional two-state Landau-Zener model and with a multistate model implying one-electron transfer between the reactant and the metal. In this context, the specifics of the dissociative adsorption of O₂ on Ag(111) are briefly discussed. The text was submitted by the author in English.     

Resonance excitations at the surface of a metal with a gyrotropic plasma coating

Gor'kii State University. Translated from Izvestiya Vysshikh Zavedenii, Radiofizika, Vol. 33, No. 6, pp. 659–665, June, 1990.     

The effective interaction suggested by direct observation for an adatom pair on a metal surface

The direct observations of the interaction of metal atoms adsorbed on a metal surface in field ion microscopy are used to choose the effective pair potential of the adatoms.     

Formation of a space charge during the interaction of an ion with a metal surface

When an ion approaches a metal surface, an induced charge forms in it, which affects the formation of electronic states in an ion-metal system. The spatial distribution of the electron density near the metal surface has been calculated in the case of the classical consideration and in the framework of the energy density functional approximation. It is shown that the space cloud exists in the form of a sphere segment; in this case, this cloud is shifted toward the approaching ion in the quantum-mechanical consideration.     

Stochastic clustering of the surface at the interaction of a plasma with materials

The inhomogeneous stochastic clustering of the surface with the self-similarity of the granularity structure from nano- to macroscales is observed in various materials after the action of intense high-temperature plasma flows in nuclear fusion facilities. The spectral and statistical characteristics of hierarchical granularity and scale invariance are estimated. They qualitatively differ from the properties of the simplest Brownian surface roughness and clustering under other conditions possibly because of universal mechanisms of the formation of stochastic clustering of materials under the action of a high-temperature plasma.     

Argon ion beam interaction on polyethylene terephthalate surface by a 4 kJ plasma focus device

Polyethylene terephthalate (PET) has a wide variety of applications ranging from making regular bottles to biosensors. However, for many of these applications, surface treatment is needed to improve its surface characteristics such as adhesion to other materials. In this study, we focussed on treating PET foils by dense Ar pulsed plasma produced by a 4.5 kJ Mather-type plasma focus device (20 kV, 40 µf, 115 nH) to examine its ability to make the PET surface hydrophilic. The most common method to examine this characteristic is measuring the water contact angle on a polymer surface. The results show that while the energy and density of plasma in our device are higher compared to other devices, as the exposure time is very low, the device can enhance the wettability of PET film surfaces.     

Band effects and the dipole interaction between two adatoms on a metal surface

The contribution of band effects to the adatom interaction energy is investigated to second order in perturbation theory. These are found to bring an important correction to the dipole law derived recently by Kohn and Lau.     

Initiation of heterogeneous photocondensation processes by laser radiation

A physical model of heterogeneous photocondensation processes initiated in a saturated-vapor atmosphere by intense laser radiation is proposed. Several mechanisms of induction of nonlinear supersaturation in the medium are examined. The concentration and maximum radius of the formed drops for a prescribed nonlinear supersaturation are calculated. It is shown that the laser-flash energy introduced initially into the medium and ensuring the transfer of the condensation nuclei across the forbidden radius gap is capable of initiating a much more energetic macroprocess of drop generation from supersaturated vapor.Part of this work was reported at the Regional Applied Science Conference, Tomsk, Oct. 27–30, 1977. Proceedings of Physicotechnical Section. Tomsk State Univ., p. 81.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 80–84, June, 1979.     

Potential surface waves at the boundary of a metal with a magnetoactive plasma at finite pressure

The propagation of surface-type potential waves along the interfacial boundary of a plasma with an ideally conducting metal in an external magnetic field perpendicular to the boundary is examined. It is shown that a necessary condition for the existence of these waves in the system is a finite gas kinetic pressure. Dispersion relations for these waves and expressions for the penetration depth of the wave fields into the plasma are obtained, and they are studied numerically for various plasma parameters. The frequency region for propagation of these waves is found. It is also shown that in a nonzero external magnetic field a system of this kind has a range of frequencies in which the wave is a generalized surface wave. Zh. Tekh. Fiz. 69, 30–33 (November 1999)     

Dynamics of ionization processes during the interaction of a microwave pulse with plasma near hybrid resonance

We experimentally investigated the dynamics of ionization processes and the formation of a plasma wave channel during the interaction of intense microwave pulses with a magnetized inhomogeneous plasma in the presence of hybrid resonance. The competition between fast electron and slow ionization plasma nonlinearities was studied under conditions when the electron oscillation energy in the wave field was much higher than the atomic ionization energy of the working gas.     

The van der Waals interaction energy between a void and a metal surface

The plasmon part of the van der Waals interaction energy between a void and a metal surface is calculated. In the limit of large z₀ (distance between the void and the surface), the interaction energy is shown to be proportional to z^-3₀ and 2 to 5 times larger than the elastic energy for copper.