JIMÉNEZ CALZADO , Carmen

La Memoria está organizada en seis capítulos y dos apéndices. En el Capítulo 1, se presenta una breve introducción a las teorías de las reacciones de transferencia electrónica. En el Capítulo 2, se discute la metodología empleada para la determinación del acoplamiento electrónico en los tres sistemas de interés. Los efectos físicos que...

La omnipresencia e importancia de las reacciones de transferencia electrónica que se dan en la naturaleza han motivado que este tipo de procesos haya constituido un tópico en la investigación química dando lugar a una voluminosa bibliografía, que se extiende en todas sus áreas, sean orgánica, inorgánica o bioquímica.El elemento común a todos...

We present the evaluation of magnetic terms in a Cu4O4 cubane-like system from truncated CI calculations, as a case study of polynuclear transition-metal complexes. We employ a new excitation selected configuration interaction (EXSCI) method based on the use of local orbitals. Taking advantage of the locality and then of the fact that the...

The four-spin operators are suspected to have a significant amplitude and an impact on the collective properties in spin ladders and magnetic two-dimensional lattices. They originate from cyclic circulation of electrons ~ring currents!. Starting from a simple Hubbard Hamiltonian one may establish their form from a fourth order expansion of...

A series of accurate ab initio calculations on CupOq finite clusters, properly embedded in the Madelung potential of the infinite lattice, have been performed in order to determine the local effective interactions in the CuO2 planes of La22xSrxCuO4 compounds. The values of the first-neighbor interactions, magnetic coupling (JNN5125 meV!, and...

The use of multireference perturbation theory (MRPT) for the calculation of the magnetic coupling in binuclear complexes has shown to give poor results if applied on a minimal active space complete active space self-consistent field (CASSCF) wavefunction. In this work, we identify the origin of this problem in the starting CASSCF orbitals,...

Metal dithiolene complexes-M(dmit)₂-are key building blocks for magnetic, conducting, and optical molecular materials, with singular electronic structures resulting from the mixing of the metal and dmit ligand orbitals. Their use in the design of magnetic and conducting materials is linked to the control of the unpaired electrons and their...

Accurate ab initio calculations on embedded Cu4O12 square clusters, fragments of the La2CuO4 lattice, confirm a value of the nearest neighbor antiferromagnetic coupling (J = 124 meV) previously obtained from ab initio calculations on bicentric clusters and in good agreement with experiment. These calculations predict non negligible...

This contribution sununarizes sorne of the theoretical strategies developed in the recent past to study systems with an increasing size and complexity by means of accurate extended CI calculations. Sorne examples ofthe capabilities of these strategies are also given, conceming the evaluation of magnetic exchange constants, as well as many ...

A common feature of spin-crossover molecules deposited on a substrate is the presence of a residual proportion of high-spin (HS) molecules at low temperature, instead of the pure low-spin (LS) phase observed in the bulk. In this work, we analyse by means of periodic rPBE calculations, the deposition of a monolayer of an Fe(II) spin-crossover...

The nature of magnetic interactions and electron transfer processes in La22xSrxCuO4 systems are studied, by means of an ab initio embedded cluster model approach, using a difference dedicated configuration interaction ~DDCI! procedure. For the undoped system, the crucial role played by the ligand to metal charge transfer ~LMCT! configurations...

Most interpretations of the magnetic coupling J between two unpaired electrons rest upon simple valence models that involve essentially the ferromagnetic direct exchange contribution, Kab , and the antiferromagnetic effect of the delocalization resulting from the interaction between neutral and ionic determinants, tab , whose energy difference...

Internally contracted state-specific multireference MR algorithms, either perturbative such as CASPT2 or NEVPT2, or nonperturbative such as contracted MR configuration interaction or MR coupled cluster, are computationally efficient but they may suffer from the internal contraction of the wave function in the reference space. The use of a low...

We present a study concerning the effect of the on site d-d Coulomb interaction energy U on the band-gap states of nonstoichiometric rutile 110 TiO2 surface. As well known, the excess electrons resulting from the formation of oxygen vacancies localize on the Ti 3d orbitals forming band-gap states. Local density approximation LDA does not...

Accurate estimates of the magnetic coupling in binuclear complexes can be obtained from ab initio configuration interaction ~CI! calculations using the difference dedicated CI technique. The present paper shows that the same technique also provides a way to analyze the various physical contributions to the coupling and performs numerical...

A key requirement for the implementation of molecular quantum dot cellular automata (mQCA) is the ordered attachment of molecules on surfaces. In this work we explore by means of stateof- the art quantum chemistry calculations different aspects of the deposition of a mixed-valence Ru2+ complex on Au(111), underlined as a promising component in...

The exchange channels governing the experimentally reported coupling constant Jexpt=6 cm−1 value in the verdazyl-ligand based Cu II complex Cu hfac 2 imvdz are inspected using wave function-based difference dedicated configuration interaction calculations. The interaction between the two spin 1/2 holders is summed up in a unique coupling...

Internally contracted state-specific multireference (MR) algorithms, either perturbative such as CASPT2 or NEVPT2, or nonperturbative such as contracted MR configuration interaction or MR coupled cluster, are computationally efficient but they may suffer from the internal contraction of the wave function in the reference space. The use of a low...

Quantum chemical calculations on embedded cluster models have been performed to extract accurate estimates of the magnetic coupling J and hopping parameters t of CaCu2O3. It is shown that this copper oxide compound is best described as a quasi-one-dimensional spin chain with weak interchain interactions within and between the Cu2O3 planes. This...

We present a method that uses the one-particle density matrix to generate directly localized orbitals dedicated to multireference wave functions. On one hand, it is shown that the definition of local orbitals making possible physically justified truncations of the CAS ~complete active space! is particularly adequate for the treatment of...

A general mapping between the energy of pertinent magnetic solutions and the diagonal terms of the spin Hamiltonian in a local representation provides the first general framework to extract accurate values for the many body terms of extended spin Hamiltonians from periodic first-principle calculations. Estimates of these terms for La2CuO4, the...

In magnetic coordination compounds and solids the magnetic orbitals are essentially located on metallic centers but present some delocalization tails on adjacent ligands. Mean field variational calculations optimize this mixing and validate a single band modelization of the intersite magnetic exchange. In this approach, due to the Brillouin's...

The BPY[Ni(dmit)2]2 molecular crystal synthesized by Naito and coworkers (J. Am. Chem. Soc., 2012, 134, 18656) was characterized as a photo-magnetic-conductor. This crystal is a nonmagnetic semiconductor in the dark and becomes a magnetic conductor after UV irradiation. This work analyzes the key ingredients of the observed photomagnetism and...

We explore the deposition of the spin-crossover [Fe(tzpy)2(NCS)2] complex on the Au(100) surface by means of density functional theory (DFT) based calculations. Two different routes have been employed: low-cost finite cluster-based calculations, where both the Fe complex and the surface are maintained fixed while the molecule approaches the...