Relaxation effects and thermal vibrations in a Pt(111) surface measured by medium energy ion scattering

Veen, J. F. van der; Smeenk, R.G.; Tromp, R. M.; Saris, F. W.

doi:10.1016/0039-6028(79)90038-4

Cited by 93 publications

(14 citation statements)

References 15 publications

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“…The surface relaxations calculated from such semiempirical methods are not reliable enough, especially for some "anomalous" surfaces, e.g. Al(100), 17,20 Al(111), 7,21 Pt(111) 22,23 and Cu(111). 14 The relaxations of the above "anomalous" surfaces are predicted to be inward relaxation from many semiempirical methods, while the experimental measurements show outward relaxation.…”

Section: Introductionmentioning

confidence: 99%

RELAXATION OF Cu(100), (110) AND (111) SURFACES USING AB INITIO PSEUDOPOTENTIALS

et al. 2001

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The geometries of the Cu(100), Cu(110) and Cu(111) surfaces are determined using ab initio pseudopotential calculations. Use of the Hellmann-Feynman theorem to calculate forces allows the determination of the equilibrium atomic positions with a small number of trial geometries. Our calculated results show that the surface relaxation of Cu(100) and Cu (110) surfaces are inward relaxations, while that of Cu(111) surface is slightly outward relaxation. Our results show that the forces, charge transfer and the detailed electronic structure of the Cu surface will affect the relaxation of the outermost layer. The calculated results are in good agreement with the results obtained by various experiments. * Corresponding author. 541 Surf. Rev. Lett. 2001.08:541-547. Downloaded from www.worldscientific.com by CAMBRIDGE UNIVERSITY on 02/02/15. For personal use only.

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Section: Introductionmentioning

confidence: 99%

RELAXATION OF Cu(100), (110) AND (111) SURFACES USING AB INITIO PSEUDOPOTENTIALS

et al. 2001

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“…Platinum surface structures have been studied using low-energy electron diffraction spectroscopy [9][10][11][12][13] ͑LEEDS͒ and ion scattering microscopy. [14][15][16] The electronic structure, instead, has been determined by means of angle-resolved photoemission experiments, 17 while ultraviolet photoemission spectroscopy has been used for accurate estimates of the Pt͑111͒ work function. 18 After the pioneering works of Lang and Kohn, [19][20][21][22][23] accurate calculations of Pt bulk and ͑111͒ surface [24][25][26][27][28][29][30][31][32][33][34] played an important role in the prediction of the behavior of the solid metal for technical applications.…”

Section: Introductionmentioning

confidence: 99%

Modeling bulk and surface Pt using the “Gaussian and plane wave” density functional theory formalism: Validation and comparison to k-point plane wave calculations

Santarossa¹,

Vargas²,

Iannuzzi³

et al. 2008

The Journal of Chemical Physics

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We present a study on structural and electronic properties of bulk platinum and the two surfaces (111) and (100) comparing the Gaussian and plane wave method to standard plane wave schemes, normally employed for density functional theory calculations on metallic systems. The aim of this investigation is the assessment of methods based on the expansion of the Kohn-Sham orbitals into localized basis sets and on the supercell approach, in the description of the metallicity of Pt. Electronic structure calculations performed at Gamma-point only on supercells of different sizes, from 108 up to 864 atoms, are compared to the results obtained for the unit cell of four Pt atoms where the k-point expansion of the wave function over Monkhorst-Pack grids up to (10x10x10) has been employed. The evaluation of the two approaches with respect to bulk properties is done through the calculation of the equilibrium lattice constant, the bulk modulus, and the total and the d-projected density of states. For the Pt(111) and Pt(100) surfaces, we consider the relaxation of the first layers, the surface energies, the work function, the total density of states, as well as the center and filling of the d bands. Our results confirm that the accuracy of two approaches in the description of electronic and structural properties of Pt is equivalent, providing that consistent supercells and k-point meshes are used. Moreover, we estimate the supercell size that can be safely adopted in the Gaussian and plane wave method in order to obtain the same reliability of previous theoretical studies based on well converged plane wave calculations available in literature. The latter studies, in turn, set the level of agreement with experimental data. In particular, we obtain excellent agreement in the evaluation of the density of states for either bulk and surface systems, and our data are also in good agreement with previous works on Pt reported in literature. We conclude that Gaussian and plane wave calculations, with simulation cells of 400-800 atoms, can be safely used in the study of chemistry related problems involving transition metal surfaces. We present a study on structural and electronic properties of bulk platinum and the two surfaces ͑111͒ and ͑100͒ comparing the Gaussian and plane wave method to standard plane wave schemes, normally employed for density functional theory calculations on metallic systems. The aim of this investigation is the assessment of methods based on the expansion of the Kohn-Sham orbitals into localized basis sets and on the supercell approach, in the description of the metallicity of Pt. Electronic structure calculations performed at ⌫-point only on supercells of different sizes, from 108 up to 864 atoms, are compared to the results obtained for the unit cell of four Pt atoms where the k-point expansion of the wave function over Monkhorst-Pack grids up to ͑10ϫ 10ϫ 10͒ has been employed. The evaluation of the two approaches with respect to bulk properties is done through the calculation of the equilibrium latt...

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“…The results of LEED experiments were the expansion of the spacing layers by (1.1Ϯ4.4)%, (0.5Ϯ0.1)%, (0.0Ϯ2.5)%, (0.0Ϯ1.1)%, and (1.3Ϯ0.4)% by Adams et al, 33 Feder et al, 34 Hayek et al, 35 Ogletree et al, 36 and Barbieri et al, 37 respectively. The results of ionscattering experiments showed the interlayer spacing expansion of (1.4Ϯ1.0)% and (0.0Ϯ0.4)%, reported by van der Veen et al 38 and Davies et al, 39 respectively. In summary, we can say that the top-layer spacing due to the relaxation is almost indistinguishable from zero if otherwise it is expanding slightly.…”

Section: Pt"111… Surface Relaxationmentioning

confidence: 64%

Ab initiolocal-orbital density-functional method for transition metals and semiconductors

Yang

1998

Phys. Rev. B

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I develop an ab initio local-orbital method for transition metals and semiconductors. The method of calculation is based on the non-self-consistent Harris functional version of the local-density approximation. In particular, I use a generalization of the method of Sankey and Niklewski to include d orbitals in the basis set, thus allowing the application to transition metals. This method is shown to produce excellent results for the band structure of crystalline Al, Si, and Pt ͑as well as other transition-metal compounds͒. This method, along with a dynamical quenching algorithm, is employed to study Pt͑111͒ surface relaxation. The results of the calculations show a slight expansion of the top-layer spacing by 0.8% relative to the bulk spacing, which is in good agreement with experiment. ͓S0163-1829͑98͒04327-6͔Computational simulations of materials have become popular because of their ability to describe the structural properties of materials, even at a level where experiments are not easily performed. First-principles methods based on plane-wave basis sets have become especially popular since Car and Parrinello 1 introduced their molecular-dynamics ͑MD͒ algorithm. Many papers have been published based on this method. However, it is still not easy to treat transition metals with a plane-wave method because many plane waves are required to describe the deep d-orbital potentials of transition metals. An alternate route is to use a local-orbital basis set. Its main advantage is that it naturally describes chemical bondings found in nature. Often only a small number of local orbitals is required to achieve a reasonable level of accuracy. A drawback of employing this basis set is, however, that the local orbitals are not orthogonal to each other, and the computation of the matrix elements is expensive relative to the plane-wave method.Sankey, Niklewski, and Drabold 2,3 introduced a localorbital method to overcome such difficulty of calculating these matrix element integrals. In particular, they developed an ab initio Harris functional scheme 4,5 with a minimal sp 3 basis set. The key idea was to increase efficiency by developing a look-up table that contained all the information necessary to calculate the matrix elements. Within the Harris functional they were able to devise a means to store all the values of the matrix elements independent of any local environment. Matrix elements were then obtained by reading from a table based on a local atomic geometry. The efficiency of the method becomes comparable to tight binding, but with an accuracy that can be close to the plane-wave methods.The Harris functional 4,5 is a non-self-consistent version of the local-density approximation ͑LDA͒. Instead of iteratively calculating the electronic charge density to reach selfconsistency, in the Harris functional one carries out calculations once with an initial charge density. The error in the total energy of the Harris functional is proportional to the square of the difference between the initial density and the true self-consistent...

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Relaxation effects and thermal vibrations in a Pt(111) surface measured by medium energy ion scattering

Cited by 93 publications

References 15 publications

RELAXATION OF Cu(100), (110) AND (111) SURFACES USING AB INITIO PSEUDOPOTENTIALS

RELAXATION OF Cu(100), (110) AND (111) SURFACES USING AB INITIO PSEUDOPOTENTIALS

Modeling bulk and surface Pt using the “Gaussian and plane wave” density functional theory formalism: Validation and comparison to k-point plane wave calculations

Ab initiolocal-orbital density-functional method for transition metals and semiconductors

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