Eduard Cremades

Bio: Eduard Cremades is an academic researcher from University of Barcelona. The author has contributed to research in topics: Density functional theory & Magnetic anisotropy. The author has an hindex of 20, co-authored 24 publications receiving 4234 citations.

Covalent radii revisited

Abstract: A new set of covalent atomic radii has been deduced from crystallographic data for most of the elements with atomic numbers up to 96. The proposed radii show a well behaved periodic dependence that allows us to interpolate a few radii for elements for which structural data is lacking, notably the noble gases. The proposed set of radii therefore fills most of the gaps and solves some inconsistencies in currently used covalent radii. The transition metal and lanthanide contractions as well as the differences in covalent atomic radii between low spin and high spin configurations in transition metals are illustrated by the proposed radii set.

Mononuclear single-molecule magnets: tailoring the magnetic anisotropy of first-row transition-metal complexes.

Abstract: Magnetic anisotropy is the property that confers to the spin a preferred direction that could be not aligned with an external magnetic field. Molecules that exhibit a high degree of magnetic anisotropy can behave as individual nanomagnets in the absence of a magnetic field, due to their predisposition to maintain their inherent spin direction. Until now, it has proved very hard to predict magnetic anisotropy, and as a consequence, most synthetic work has been based on serendipitous processes in the search for large magnetic anisotropy systems. The present work shows how the property can be predicted based on the coordination numbers and electronic structures of paramagnetic centers. Using these indicators, two CoII complexes known from literature have been magnetically characterized and confirm the predicted single-molecule magnet behavior.

Origin of slow magnetic relaxation in Kramers ions with non-uniaxial anisotropy

Abstract: Transition metal ions with long-lived spin states represent the minimum size magnetic bit. Here, the authors study the spin–lattice relaxation of a cobalt(II) complex and demonstrate the role of time-reversal symmetry that hinders direct spin–phonon processes regardless of the sign of the magnetic anisotropy.

Molecular single-bond covalent radii for elements 1-118.

Abstract: A self-consistent system of additive covalent radii, R(AB)=r(A) + r(B), is set up for the entire periodic table, Groups 1-18, Z=1-118. The primary bond lengths, R, are taken from experimental or theoretical data corresponding to chosen group valencies. All r(E) values are obtained from the same fit. Both E-E, E-H, and E-CH 3 data are incorporated for most elements, E. Many E-E' data inside the same group are included. For the late main groups, the system is close to that of Pauling. For other elements it is close to the methyl-based one of Suresh and Koga [J. Phys. Chem. A 2001, 105, 5940] and its predecessors. For the diatomic alkalis MM' and halides XX', separate fits give a very high accuracy. These primary data are then absorbed with the rest. The most notable exclusion are the transition-metal halides and chalcogenides which are regarded as partial multiple bonds. Other anomalies include H 2 and F 2 . The standard deviation for the 410 included data points is 2.8 pm.

Recent advances in homogeneous nickel catalysis

Abstract: Tremendous advances have been made in nickel catalysis over the past decade Several key properties of nickel, such as facile oxidative addition and ready access to multiple oxidation states, have allowed the development of a broad range of innovative reactions In recent years, these properties have been increasingly understood and used to perform transformations long considered exceptionally challenging Here we discuss some of the most recent and significant developments in homogeneous nickel catalysis, with an emphasis on both synthetic outcome and mechanism

The puzzle of high temperature superconductivity in layered iron pnictides and chalcogenides

Abstract: The response of the worldwide scientific community to the discovery in 2008 of superconductivity at T c = 26 K in the Fe-based compound LaFeAsO1−x F x has been very enthusiastic. In short order, ot...

Two-dimensional materials from high-throughput computational exfoliation of experimentally known compounds

Abstract: Two-dimensional (2D) materials have emerged as promising candidates for next-generation electronic and optoelectronic applications. Yet, only a few dozen 2D materials have been successfully synthesized or exfoliated. Here, we search for 2D materials that can be easily exfoliated from their parent compounds. Starting from 108,423 unique, experimentally known 3D compounds, we identify a subset of 5,619 compounds that appear layered according to robust geometric and bonding criteria. High-throughput calculations using van der Waals density functional theory, validated against experimental structural data and calculated random phase approximation binding energies, further allowed the identification of 1,825 compounds that are either easily or potentially exfoliable. In particular, the subset of 1,036 easily exfoliable cases provides novel structural prototypes and simple ternary compounds as well as a large portfolio of materials to search from for optimal properties. For a subset of 258 compounds, we explore vibrational, electronic, magnetic and topological properties, identifying 56 ferromagnetic and antiferromagnetic systems, including half-metals and half-semiconductors.

Jaguar: A high-performance quantum chemistry software program with strengths in life and materials sciences

Abstract: Jaguar is an ab initio quantum chemical program that specializes in fast electronic structure predictions for molecular systems of medium and large size. Jaguar focuses on computational methods with reasonable computational scaling with the size of the system, such as density functional theory (DFT) and local second-order Moller–Plesset perturbation theory. The favorable scaling of the methods and the high efficiency of the program make it possible to conduct routine computations involving several thousand molecular orbitals. This performance is achieved through a utilization of the pseudospectral approximation and several levels of parallelization. The speed advantages are beneficial for applying Jaguar in biomolecular computational modeling. Additionally, owing to its superior wave function guess for transition-metal-containing systems, Jaguar finds applications in inorganic and bioinorganic chemistry. The emphasis on larger systems and transition metal elements paves the way toward developing Jaguar for its use in materials science modeling. The article describes the historical and new features of Jaguar, such as improved parallelization of many modules, innovations in ab initio pKa prediction, and new semiempirical corrections for nondynamic correlation errors in DFT. Jaguar applications in drug discovery, materials science, force field parameterization, and other areas of computational research are reviewed. Timing benchmarks and other results obtained from the most recent Jaguar code are provided. The article concludes with a discussion of challenges and directions for future development of the program. © 2013 Wiley Periodicals, Inc.