Showing papers by "José M. Soler published in 2007"

Separating the articles of authors with the same name

Abstract: I describe a method to separate the articles of different authors with the same name. It is based on a distance between any two publications, defined in terms of the probability that they would have as many coincidences if they were drawn at random from all published documents. Articles with a given author name are then clustered according to their distance, so that all articles in a cluster belong very likely to the same author. The method has proven very useful in generating groups of papers that are then selected manually. This simplifies considerably citation analysis when the author publication lists are not available.

Formation of gold nanowires with impurities: a first-principles molecular dynamics simulation.

Abstract: We present first-principles molecular dynamics simulations of the formation of monatomic gold nanowires with different impurities (H, C, O, S). Special care was taken not to bias the probability that the impurity atoms participate in the monatomic wire, which is the main focus of this work. Hydrogen always evaporated before the formation of the monatomic chains. Carbon and oxygen were found in the final chains with low probability ( approximately 10%), while sulfur almost always participated in it (probabability approximately 90%). The mean distances between gold atoms bridged by carbon, oxygen, and sulfur were 3.3, 4.4, and 5.0 A, respectively, in good agreement with experimental observations. The contributions of carbon, oxygen, and sulfur to the density of electronic states at the Fermi level are neglegible, moderate, and large, respectively.

Design of molecular wires based on one-dimensional coordination polymers

Abstract: The authors report the results of ab initio calculations for the structural and electronic properties of one-dimensional coordination polymers with the general formula [M(6-MP)2]n (where 6-MP=6-mercaptopurinate, and M=MnII, FeII, CoII, NiII, and CuII). A common stable structure, consistent with the experimental data for [Cd(6-MP)2]n, is found for all metal cations studied, with the exception of MnII. Polymers containing FeII, NiII, and CoII are found to be ferromagnetic semiconductors, while [Cu(6-MP)2]n shows a Peierls-unstable paramagnetic metallic phase that undergoes a transition to a ferromagnetic semiconductor one under small stretching.

Order- N and embedded-cluster first-principles DFT calculations using SIESTA/Mosaico

Abstract: Order-N and embedded-cluster first-principles DFT calculations have been performed with the Mosaico method for energy optimization (Seijo and Barandiaran in J Chem Phys 121:6698, 2004) for the first time. The Hamiltonian matrix elements have been computed with the SIESTA code. The order-N behavior of the method in DFT calculations was shown in total energy calculations performed on bulk silicon using supercells up to Si8000. The sizes of the orbital-specific-basis-sets needed for precise calculations have been explored in demanding (bulk silicon) and favorable (water clusters) cases for a method based on the calculation of localized molecular orbitals. Embedded-cluster calculations, which are much faster than full-system calculations, have been performed on an Si-vacancy of bulk silicon and on a water cluster with a displacing water molecule. The feasiability of calculations of this type with Mosaico has been demonstrated. The sizes of the variationally free, active clusters which are needed for an agreement with full-system calculations have been explored and result to be reasonably small.