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We present a method for density-functional modeling of metallic overlayers grown on a support. It offers a useful tool to study nanostructures, combining the power of self-consistent pseudopotential calculations with the simplicity of a one-dimensional approach. The model is illustrated for Pb layers grown on the Cu(111) surface. The analysis provides the strength of the electron confinement barriers in thin slabs with accuracy, supporting the interpretation of the quantum well state spectra measured by scanning tunneling spectroscopy. On the other hand, it offers a benchmark to check the simple analytical models commonly used in the literature to study metallic films on semiconducting or metallic surfaces. As a result, some deficiencies are detected in the applicability of those models, which often lead to an overestimation of the number of wetting layers. Finally, an improved formula is proposed., We acknowledge partial support by the University of the Basque Country s9/UPV00224.310-14553/2002d, the Basque Hezkuntza Unibertsitate eta Ikerkuntza Saila and the Spanish Ministerio de Ciencia y Tecnología MAT 2001-0946 and MAT2002-04087-CO2-O1d. This work was also partially supported by the Academy of Finland through its Centre of Excellence Program s2000–2005d and by the European Community sixth Framework Network of Excellence NANOQUANTA sNMP4-CT-2004-500198d.

Recently, a low-energy collective excitation has been predicted to exist at metal surfaces where a quasi two-dimensional (2D) surface-state band coexists with the underlying three-dimensional (3D) continuum. Here we present a model in which the screening of a semiinfinite 3D metal is incorporated into the description of electronic excitations in a 2D electron gas through the introduction of an effective 2D dielectric function. Our self-consistent calculations of the dynamical response of the 3D substrate indicate that an acoustic surface plasmon exists for all possible locations of the 2D sheet relative to the metal surface. This low-energy excitation, which exhibits linear dispersion at low wave vectors, is dictated by the nonlocality of the 3D dynamical response providing incomplete screening of the 2D electron-density oscillations., Partial support by the University of the Basque Country, the Basque Unibertsitate eta Ikerketa Saila, the SpanishcMCyT, and the Max Planck Research Award Funds is gratefully acknowledged. V.U.N. acknowledges support by the Korea Research Foundation through Grant No. KRF-2003-015-C00214 and the hospitality of the Donostia International Physics Center (DIPC).

arXiv:cond-mat/0402273v1, A novel collective excitation is predicted to exist at metal surfaces where a two-dimensional surface state band coexists with the underlying three-dimensional continuum. This is a low-energy acoustic plasmon with linear dispersion at small wave vectors. Since new modern spectroscopies are especially sensitive to surface dynamics near the Fermi level, the existence of surface-state–induced acoustic plasmons is expected to play a key role in a large variety of new phenomena and to create situations with potentially new physics., Partial support by the University ofthe Basque Country, the Basque Unibertsitate eta Ikerketa Saila, the Spanish MCyT, and the Max Planck Research Award Funds is gratefully acknowledged.

Using first-principles calculations and angle-resolved photoemission, we show that the spin-orbit interaction leads to a strong splitting of the surface-state bands on low-index surfaces of Bi. The dispersion of the states and the corresponding Fermi surfaces are profoundly modified in the whole surface Brillouin zone. We discuss the implications of these findings with respect to a proposed surface charge density wave on Bi(111) as well as to the surface screening, surface spin-density waves, electron (hole) dynamics in surface states, and to possible applications to the spintronics., This work was partially supported by the UPV/EHU, Spanish MCyT, the Max Planck Research Award Fund, and by the Danish National Science Foundation.

The role that occupied d bands play in the inelastic lifetime of bulk and surface states in Ag is investigated from the knowledge of the quasiparticle self-energy. In the case of bulk electrons, sp bands are taken to be free-electron-like. For surface states, the surface band structure of sp states is described with the use of a realistic one-dimensional Hamiltonian. The presence of occupied d states is considered in both cases by introducing a polarizable background. We obtain inelastic lifetimes of bulk electrons that are in good agreement with first-principles band-structure calculations. Our surface-state lifetime calculations indicate that the agreement with measured lifetimes of both crystal-induced and image-potential-induced surface states on Ag(100) and Ag(111) is considerably improved when the screening of d electrons is taken into account., We acknowledge partial support by the University of the Basque Country, the Basque Unibertsitate eta Ikerketa Saila, the Spanish Ministerio de Ciencia y Tecnologia, and the Max Planck Research Funds.

The Be electron inelastic mean free path (IMFP) is calculated by using the GW approximation of many-body theory. It is demonstrated that the inclusion of band structure effects significantly improves the agreement between the calculated and measured IMFP in the energy range up to ∼30eV. We show that the main effect results from the electron group velocity obtained from ab initio band structure calculations, whereas the evaluated linewidth averaged over momenta is not significantly affected with respect to the prediction of a free electron gas model. The comparison of the IMFP computed within two models, namely, the free electron gas model and the full band structure model, supports the idea of the importance of band structure effects for the description of electron transport in this metal for energies below 30 eV, and a nearly free-electron-like behavior for excitation energies above 30 eV. The calculated plasmon dispersion is in excellent agreement with available experimental data., We acknowledge partial support by the University of the Basque Country, the Departamento de Educacion del Gobierno Vasco, and the Spanish Ministerio de Educacion y Cultura

We present a first principle study of the electron-phonon (e−p) interaction at the Be(0001) surface. The real and imaginary parts of the e−p self-energy (Σ) are calculated for the ¯¯¯Γ surface state in the binding energy range from the ¯¯¯Γ point to the Fermi level. Our calculation shows an overall good agreement with several photoemission data measured at high and low temperatures. Additionally, we show that the energy derivative of ReΣ presents a strong temperature and energy variation close to EF, making it difficult to measure its value just at EF., We acknowledge financial support from the Basque Government, the Max Planck Research Award Funds, the Spanish Ministerio de Educacion y Ciencia (MEC), and the Basque Country University.

Theoretical calculations and scanning-tunneling spectroscopy measurements of the hole lifetime broadening, τ−1, in a quantum-well state for 0.95 and 1.0 monolayers of Na on Cu(111) are reported. A model potential is proposed for calculating quantum-well states in a monolayer on metal surfaces. The inelastic electron-electron contribution, τ−1e−e, is evaluated within the GW approximation by using eigenfunctions and eigenenergies obtained with this model potential. The electron-phonon contribution, τ−1e−ph, is computed by employing Debye and Einstein models as well as a first-principle ultrasoft pseudopotential method. The obtained theoretical results are in excellent agreement with experimental data, both showing a surprisingly large difference in the lifetime broadening for 0.95 and 1.0 monolayers which is attributed mostly to changes in the electronic structure., We acknowledge partial support by the University of the Basque Country, the Basque Hezkuntza Unibertsitate eta Ikerreta Saila, and Ministerio de Ciencia y Tecnologia Grant No. MAT 2001-0946. Financial support by the Deutsche Forschungsgemeinschaft and Deutscher Akademischer Austauschdienst is gratefully acknowledged. The work was also financially supported by the Swedish Scientific Research Council VR. P.M.E. acknowledges support from the Max Planck Foundation; S.C. acknowledges the support of British Council.

Ab initio calculation of the density response function within the random-phase approximation is presented for lithium, berillium, and boron freestanding metal monolayers (ML’s). Although the monolayers manifest common features related to their reduced dimensionality, their different band structures lead to significant modifications in the density response function. Besides the common intraband and interband collective excitations, the beryllium ML also presents characteristic features of acoustic plasmons associated with the presence of two types of carriers at the Fermi level. Contrary to the bulk, long-wavelength intraband plasmons in lithium and beryllium ML’s cannot decay via umklapp processes associated with the band structure. At the same time, these processes lead to a significant reduction of the momentum threshold for decay of these plasmons comparing with a free-electron two-dimensional gas model. It is also shown how a change of the symmetry of the boron ML modifies completely the character of the intraband plasmons., The authors acknowledge partial support by the University of the Basque Country, the Basque Hezkuntza, Unibertsitate eta Ikerketa Saila, the Spanish Ministerio de Educacion y Cultura.

We present results of a theoretical investigation of the phonon-mediated decay of metal surface states. The calculated energy- and temperature-dependent lifetime broadening of a hole as well as the electron-phonon coupling parameter for the surface-state band on Al(100), Ag(111), Cu(111) and Au(111) are given. A detailed analysis of the Eliashberg spectral function shows that the intraband scattering is of minor importance for these systems. The surface Rayleigh phonon mode is shown to be crucial for the surface-state decay on the noble metal surfaces, in particular for energies close to the Fermi level where the Rayleigh mode is responsible for the major part of the phonon induced lifetime broadening., We acknowledge financial support from the Basque Government, the Max Planck Research Award Funds, the Spanish Ministerio de Educacion y Ciencia (MEC), the Basque Country Univesity, and the Carl Tryggers Foundation.

We report on theoretical studies of hole lifetimes in Cu and Au by means of the ab initio all electron full potential linear method of “muffin-tin” orbitals approach. We find that the momentum-averaged d-hole lifetimes in Cu, Au deviate much less from the lifetimes of holes in free-electron-like s,p bands than it was found in previous ab initio studies. However, at symmetry points L and X and along the X−W direction of the Brillouin zone the differences between the lifetimes of d holes and s,p holes are big. The lifetime of a hole in the top X5 d state of Cu is in good agreement with the experimental data. The lifetimes for lower d states deviate from experimental results, which we refer to neglecting spin-orbit coupling and interactions described by higher order terms of many-body perturbation theory. We discuss the calculational details responsible for the precision of the lifetime evaluations., The support by the University of the Basque Country, the Basque Hezkuntza Saila, the Spanish Ministerio de Education y Cultura, and the Max Planck Grant for international cooperation are gratefully acknowledged.

Surface chemical reactions are influenced by inherent dissipative processes which involve energy transfer between the conduction electrons and the ionic motion. We will discuss how it is possible to model this electron–phonon coupling in order to estimate its importance. A relevant quantity for this investigation is the lifetime of surface localized electron states. A surface state, quantum-well state or surface image state is located in a surface projected band gap and becomes relatively sharp in energy. This makes a comparison between calculations and experimental data most attractive, with a possibility to resolve the origin of the lifetime broadening. We point out the importance of taking into account the phonon spectrum, electron surface state wave functions and the screening of the electron–ion potential., We acknowledge partial support by the Basque Country Government, the University of the Basque Country, Ministerio de Ciencia y Tecnologia.

The electronic structure of the Ni3Al(001) surface is calculated using the self-consistent film linearized augmented- plane-wave method. As a result, surface states both above and below the Fermi level have been found. Practically, all the occupied surface states are generated by the atoms of nickel. There is only one occupied state at the M point localized at the surface atoms of aluminium. The states above the Fermi level are mainly localized at the Al atoms of the surface layer. There are states totally generated by the atoms of aluminium. Calculated work function exceeds the corresponding values for the Ni(001) and Al(001) surfaces.

We report the theoretical studies of electron and hole lifetimes in Nb, Mo, Rh, Pd, Ag by means of an ab initio many-body GW method and of a semiempirical scattering-theory approach (STA). The GW approach includes the evaluation of band structures within the local-density approximation linear muffin-tin orbital TB formalism and employment of random-phase approximation in the calculations of the dielectric functions and screened Coulomb interaction. We show that the density-of-states (DOS) convolution model of the STA provides a good approximation to the ab initio averaged lifetimes, the energy dependence of the matrix element being rather unimportant. We discuss the role of the characteristics of electronic structure responsible for the deexcitation of hot electrons as well as the deviations of the ab initio lifetimes from the predictions of the free-electron gas model and the DOS convolution model.

The combined effect of single-particle and collective surface excitations in the decay of image-potential states on Ag surfaces is investigated, and the origin of the long-standing discrepancy between experimental measurements and previous theoretical predictions for the lifetime of these states is elucidated. Although surface-plasmon excitation had been expected to reduce the image-state lifetime, we demonstrate that the subtle combination of the spatial variation of s−d polarization in Ag and the characteristic nonlocality of many-electron interactions near the surface yields surprisingly long image-state lifetimes, in agreement with experiment., We acknowledge partial support by the University of the Basque Country, the Basque Unibertsitate eta Ikerketa Saila, the Spanish Ministerio de Educacion y Cultura, and the Max Planck Research Award Funds.

Chemical reactions at metal surfaces are influenced by inherent dissipative processes which involve energy transfer between the conduction electrons and the nuclear motion. We shall discuss how it is possible to model this electron-phonon coupling in order to estimate its importance. A relevant quantity for this investigation is the lifetime of surface-localized electron states. A surface state, quantum well state or surface image state is located in a surface-projected bandgap and becomes relatively sharp in energy. This makes a comparison between calculations and experimental data most attractive, with a possibility of resolving the origin of the lifetime broadening of electron states. To achieve more than an order of magnitude estimate we point out the importance of taking into account the phonon spectrum, electron surface state wavefunctions and screening of the electron-ion potential., We acknowledge partial support by the Basque Country Government, the University of the Basque Country, Ministerio de Ciencia y Tecnologia

We report theoretical studies of electron and hole lifetimes in a free-electron gas as well as in real metals Al and Nb by means of the ab initio many-body method and semi-empirical scattering theory approach. We show that for free-electron-like excitations a simple density-of-state convolution model of the scattering theory approach (STA-DOS) is a good approximation to the ab initio lifetimes, the energy dependence of the STA-DOS transition matrix element being rather unimportant. The approximation of energy-independent matrix element appears to also be reasonable for Nb. A good correspondence between the STA-DOS and ab initio momentum-averaged results is achieved for Nb with an adjusted matrix element, although the ab initio lifetimes disperse greatly with respect to the averaged value., This work was partially supported by the Basque Country University and Basque Hezkuntza Saila.

We present a comprehensive theoretical investigation of the electron-phonon contribution to the lifetime broadening of the surface states on Cu(111) and Ag(111), in comparison with high-resolution photoemission results. The calculations, including electron and phonon states of the bulk and the surface, resolve the relative importance of the Rayleigh mode, being dominant for the lifetime at small hole binding energies. Including the electron-electron interaction, the theoretical results are in excellent agreement with the measured binding energy and temperature dependent lifetime broadening., We acknowledge financial support from the Basque Government, the Deutsche Forschungsgemeinschaft (SFB 277), the Carl Tryggers Foundation and the Max Planck Research Award Funds

We present self-consistent pseudopotential calculations of surface and image-potential states on ${\mathrm{MgB}}_{2}(0001)$ for both B-terminated $(\mathrm{B}\ensuremath{-}t)$ and Mg-terminated $(\mathrm{Mg}\ensuremath{-}t)$ surfaces. We find a variety of very clear surface and subsurface states as well as resonance image-potential states $n=1,2$ on both surfaces. The surface layer density of states (DOS) at ${E}_{F}$ is increased by $55%$ at the $B\ensuremath{-}t$ and by $90%$ at the $\mathrm{Mg}\ensuremath{-}t$ surface compared to DOS in the corresponding bulk layers.

We have investigated the lifetimes of image-potential states on the Pt(111) surface with time-resolved two-photon photoemission and first-principles calculations. Electrons populating the first two image-potential states decay into bulk states after 26±7 and 62±7 fs, respectively. This is in agreement with results of theoretical calculations. Oxygen adsorption reduces the image-potential state lifetimes by a factor of 2. This is caused by a strong change of the electronic structure near the Fermi level., The authors gratefully acknowledge support from the TMR network Contract No. FMRX-CT-0178 and financial support from Max-Plank-Universitat.

The frequency- and momentum-dependent dielectric function ε(q,ω) as well as the energy loss function Im[−ε−1(q,ω)] are calculated for intermetallic superconductor MgB2 by using two ab initio methods: the plane-wave pseudopotential method and the tight-binding version of the linear muffin-tin orbital method. We find two plasmon modes dispersing at energies ∼2–8eV and ∼18–22eV. The high energy plasmon results from a free electron like plasmon mode while the low energy collective excitation has its origin in a peculiar character of the band structure. Both plasmon modes demonstrate clearly anisotropic behavior of both the peak position and the peak width. In particular, the low energy collective excitation has practically zero width in the direction perpendicular to boron layers and broadens in other directions., This work was partially supported by the Basque Country University, Basque Hezkuntza Saila, and Iberdrola S.A.

Theoretical investigations of surface-state electron dynamics in noble metals are reported. The dynamically screened interaction is computed, within many-body theory, by going beyond a free-electron description of the metal surface. Calculations of the inelastic linewidth of Shockley surface-state electrons and holes in these materials are also presented. While the linewidth of excited holes at the surface-state band edge (${\bf k}_\parallel=0$) is dominated by a two-dimensional decay channel, within the surface-state band itself, our calculations indicate that major contributions to the electron-electron interaction of surface-state electrons above the Fermi level come from the underlying bulk electrons., 17 pages, 7 figures, to appear in Prog. Surf. Sci

A metal surface generates electron states that do not exist in a bulk metal. These so-called surface states can be classified into two categories, crystal-induced (intrinsic) states and image-potential-induced (image) states. Here we present a survey of current investigations on the origin of the decay of these surface states. Inelastic lifetimes are obtained from the knowledge of the quasiparticle self-energy, which we compute, within the GW approximation of many-body theory, by going beyond a free-electron description of the surface. Surface-state lifetimes in noble metal surfaces are presented. Our results show that actual lifetimes are highly sensitive to the details of the surface response and to the presence of the intrinsic surface state itself., This work was partially supported by the University of the Basque Country, the Basque Hezkuntza, Unibertsitate eta Ikerketa Saila, and the Spanish Ministerio de Educacion y Cultura. P.M.E. gratefully acknowledges support from the Max Planck Research Award funds.

We present a self-consistent pseudopotential calculation of image potential states on the Be(101¯0) surface. The one-electron potential inside the crystal and surface region is described by the local density approximation and by the image potential in the vacuum region (at z>zim). The calculated first image state (E1=−1.20 eV) lies in the symmetry gap and the second image state (E2=−0.31 eV) is located inside the absolute energy gap. High anisotropy of the dispersion of both image states is found. The effective masses that reflect this anisotropy are obtained m*1/me=1.55±0.1, m*2/me=1.30±0.1 along the ¯Γ¯M direction and m*1/me=0.40±0.05, m*2/me=0.55±0.05 along ¯ΓĀ. The unusual dispersion of the image states on Be(101¯0) is due to a large penetration value pn of these states (p1=0.34 and p2=0.15), and the very anisotropic character of the symmetry energy gap edges., This project has been supported by the Ministerio de Educacion y Ciencia, Spain; the Departamento de Educacion del Gobierno Vasco; and Iberdrola S.A.

The role of the intrinsic surface state (n=0) in the decay of the first image state (n=1) at the (111) surface of copper is investigated. Inelastic linewidths are evaluated from the knowledge of the imaginary part of the electron self energy, which we compute, within the GW approximation of the many-body theory, by going beyond a free-electron description of the metal surface. Single-particle wave functions are obtained by solving the Schrödinger equation with a realistic one-dimensional model potential, and departure of the motion along the surface from free-electron behavior is considered through the introduction of the effective mass. The decay of the first image state of Cu(111) into the intrinsic surface state is found to result in a linewidth that represents 40% of the total linewidth. The dependence of linewidths on the momentum of the image state parallel to the surface is also investigated., This project has been supported by Eusko Jaurlaritza -Basque Country, the Ministerio de Educacion y Cultura (Spain), and Iberdrola S.A.

The lifetime of image states, which represent a key quantity to probe the coupling of surface electronic states with the solid substrate, have been recently determined for quantum numbers $n\le 6$ on Cu(100) by using time-resolved two-photon photoemission in combination with the coherent excitation of several states (U. H\"ofer et al, Science 277, 1480 (1997)). We here report theoretical investigations of the lifetime of image states on copper surfaces. We evaluate the lifetimes from the knowledge of the self-energy of the excited quasiparticle, which we compute within the GW approximation of many-body theory. Single-particle wave functions are obtained by solving the Schr\"odinger equation with a realistic one-dimensional model potential, and the screened interaction is evaluated in the random-phase approximation (RPA). Our results are in good agreement with the experimentally determined decay times., Comment: 4 pages, 1 figure, to appear in Phys. Rev. Lett

We present results of a comparative study of the vibrational spectrum and local density of phonon states in ordered p(2 × 2) and (√3 × √3)R30° structures formed by potassium atoms on the Pt(111) surface. The calculations were performed with tight-binding interatomic interaction potentials. It was found that the mode associated with vertical displacements of K adatoms has an energy of about 20 meV in both K structures. The strength and energy of this mode slightly decreases with increasing coverage. This result is in good agreement with available experimental data. As in time-resolved second harmonic generation measurements, we observed low frequency modes for both structures considered, which are caused by the interaction of potassium with the second layer of the substrate. © 2012 IOP Publishing Ltd., We acknowledge financial support by the RFBR (Proj. N 11-08-00460-a).

10 pages., We review the current progress in the understanding of vibrations of alkalis adsorbed on metal surfaces. The analysis of alkali vibrations was made on the basis of available theoretical and experimental results. We also include in this discussion our recent calculations of vibrations in K/Pt(111) and Li(Na)/Cu(001) systems. The dependence of alkali adlayer localized modes on atomic mass, adsorption position and coverage as well as the dependence of vertical vibration frequency on the substrate orientation is discussed. The square root of atomic mass dependence of the vertical vibration energy has been confirmed by using computational data for alkalis on the Al(111) and Cu(001) substrates. We have confirmed that in a wide range of submonolayer coverages the stretch mode energy remains nearly constant while the energy of in-plane polarized modes increases with the increase of alkali coverage. It was shown that the spectrum of both stretch and in-plane vibrations can be very sensitive to the adsorption position of alkali atoms and substrate orientation., The work was partially supported by the Basque Country University and the Siberian Branch of RAS (grant No. 206). GB is grateful to the Donostia International Physics Center for supporting his visit to DIPC.

5 pages., Using scanning tunneling spectroscopy and first-principles calculations, we have studied the electronic structure of two different ultrathin bismuth films on a Si(111)-7×7 substrate; a hexagonal film (HEX film) having a bulklike (A7-like) structure and a film having a black-phosphorus-like structure (BP film). The HEX film is metallic because of spin–orbit (SO)-split surface-state bands lying inside the projected bulk band gap near the Fermi level. Another SO-split surface state is also observed inside the SO gap. The BP film exhibits a significant reduction in metallicity in contrast to the HEX film. This is related to the formation of a very stable paired-layer structure, the mechanism of which is similar to that of the stabilization of semiconducting bulk black P. However, unlike bulk black P, a certain extent of metallicity still remains. This slight metallicity can be associated with buckling and strain in the BP film, which is analogous to the fact that shear angle distortion in bulk Bi is responsible for its semimetallicity.

In this paper we give a detailed analysis of the difference between the lifetimes of Yb quantum-well states measured by scanning tunneling spectroscopy (STS) in Wegner et al (2005 Phys. Rev. Lett. 94 126804) and the lifetimes of bulk Yb obtained by means of time-resolved two-photon photoemission spectroscopy (TR-2PPE). In particular, we show that in spite of a seeming disagreement with the TR-2PPE measurements, the inelastic lifetimes yielded in STS experiments are close to the inelastic lifetimes of bulk states, emphasizing the complementarity of both methods. Our approach is supported by ab initio electron self-energy calculations performed within the GW and GW+T approximations. Moreover we analyze the impact of the 4f-states on the lifetimes. We show that the GW-term of the inverse lifetime (linewidth) is markedly smaller than the experimental linewidth. The agreement with experimental data is recovered when the T-matrix is included in the linewidth calculations., This work was partially supported by the University of the Basque Country UPV/EHU (grant no. 9/UPV 00206.215-13639/2001), and the Spanish MCyT (grant no. FIS2004-06490-CO3-00).

Using the pseudopotential approximation and pair core-core interaction potentials the interface vibrational modes for the Ag(001)Au(001), Ag(011)Au(011) and Ag(111)Au(111) interfaces have been calculated. The interface phonon modes localized on one side of the boundary between the constituent solids have been found for all the interfaces studied. The phonons localized on both sides of the boundary were observed at the Ag(011)Au(011) and Ag(111)Au(111) interfaces. In the case of the (001) boundary there are interface modes lying outside the bulk vibrational spectrum of Au and Ag. At other interfaces similar modes do not exist. It is shown that a subtitutional disordering at the interfaces changes the vibrational interface structure.

Expressions are obtained for calculating the binding energy of an arbitrary complex formed from impurity atoms and vacancies. Calculations are made for various complexes formed from magnesium and zinc impurity atoms and vacancies in aluminum. The results obtained are used to study the role of vacancies in the formation of Guinier-Preston zones. The need to allow for the lattice relaxation is demonstrated.

The surface electronic structure of Be(0001) and Mg(0001) is calculated self-consistently using the pseudopotential method. The first-principle non-local soft pseudopotentials of Be and Mg have been constructed in the local density functional approximation. The surface electronic structure was determined for ten-layer films of Be and Mg. An analysis of the surface and resonance states is given in terms of their distribution in the two-dimensional surface Brillouin zone, the charge density distribution, and the local density of states. The results are in good agreement with recent angle-resolved photoemission investigations.

The first-principles non-local singular atomic pseudopotentials are constructed for seventy-five elements of the Periodic Table. The pseudopotentials are calculated with account of norm-conserving. The energy dependence of the constructed pseudopotentials is studied. They are shown to be energy independent within the energy range which is characteristic of low-energy electron excitations in solids. The values of the classical turning points of pseudopotential are calculated for all the elements considered. [Russian Text Ignored]

The local density function approximation is used to construct a fundamental nonlocally soft pseudopotential for aluminum which satisfies the norm conservation condition. This pseudopotential is used to perform a self-consistent calculation of the aluminum electron energy spectrum, which proves to agree well with experimental data. The effect of various pseudopotentials (constructed with norm conservation) on the form of the energy spectrum is studied. It is shown that these various pseudopotentials lead to identical results.

The self-consistent Pseudopotential method is used to calculate the electronic structure of a Na halfmonolayer on the Al(001) surface. Surface and subsurface states are found on the Al(001)+ c(2 × 2)Na surface. The surface states are generated by the Na layer, many subsurface states originate from the true surface state of Al(001). The calculated work function 2.8 eV is in very good agreement with the experimental value 2.75 eV for pure sodium. These results indicate that (a) electronic properties of the A1(001) + c(2 × 2)Na surface are determined mainly by the Na halfmonolayer, (b) the Na halfmonolayer weakly influences the electronic structure of the Al substrate.

Values of the vacancy formation energy have been calculated in polyvalent metals Be, Mg, Zn, Tl, and Sc, without taking into account lattice relaxation energy. Parameters of the model pseudopotential used in the calculations were determined from experimental phonon spectra. Sensitivity of the quantities calculated to the choice of the approximation for exchange-correlation corrections in the dieletric function has been studied.

Pseudopotential theory is used to study the dependence of energy of vacancy formation EIVf in binary replacement alloys as a function of the degree of far order η is shown that EIVf=Eo+δE·η]2, where Eo is the energy of vacancy formation in a disordered alloy, δE then contains the ordering energy. It is shown with examples of the alloys CuZn, AuZn, and AgCd that the energy of vacancy formation can decrease with increase in the degree of far order. It is found that in calculating the vacancy formation energy it is necessary to consider lattice relaxation energy, since such consideration can lead to a change in the sign of δE.

The achievements of electron theory in investigation of the electronic and atomic properties of metal surfaces are reviewed for simple metals. The local density functional approach is used to describe the electron-electron interaction. The results of first-principles calculations of true surface and resonance surface states, charge density distributions, work function, surface layer geometry and surface phonon frequencies are given. The influence of adsorbed layers on the surface electronic characteristics is investigated. The prospects of this method for studying metal surfaces in electric fields as well as for studying the metal-electrolyte interface are outlined.