ICMCB

Simple versatile processes combining plasma treatments, micro-contact printing (µCP) or ink-jet printing (IJP), and electroless deposition (ELD) have been developed to produce micrometer and sub-micrometer scale metal (Ni, Ag) patterns at the surface of polymer substrates. Plasma treatments were mainly used to graft the substrate surfaces with either nitrogen-containing functionalities on which a palladium-based catalyst can be subsequently chemisorbed (case of Ni deposition through a tin-free process in solution) or oxygen-containing functionalities on which a tin-based sensitization agent can be subsequently chemisorbed (case of Ag deposition through a redox reaction). µCP of the catalyst or of self-assembled monolayers (SAMs) as well as ink printing were used to obtain locally active or non-active areas at the polymer surfaces. The metal micro-patterns were characterized using optical microscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). Surface chemical characterization was carried out by X-ray photoelectron spectroscopy (XPS).

For spin crossover SCO complexes, computation results are reported and confronted with experiment at the multi-scale levels of the isolated molecule and extended solid. The SCO phenomenon which characterizes organometallics based on divalent iron in octahedral FeN 6 -like environment with high spin (HS) and low spin (LS) states involves the LS/HS switching at the cost of small energies provided by temperature, pressure or light, the latter connected with Light-Induced Excited Spin-State Trapping (LIESST) process. Characteristic IR and Raman frequencies are computed within density functional theory DFT framework and confronted with experiment. In [Fe(phen) 2 (NCS) 2 ] a connection of selected frequencies is established with ultra-fast light induced LSHS photoswitching mechanism. In extended solids, LS/HS density of state DOS and electron localization function ELF are established. In [Fe(PM-BIA) 2 (NCS) 2 ], by combining DFT and classical molecular dynamics the properties and the domains of existence of the different phases are obtained by expressing the potential energy surfaces in a short range potential mainly for Fe-N. Applying such Fe-N potentials inserted in a classical force field and carrying out molecular dynamics MD in so-called 'semi-classical MD' calculations, lead to the relative energies of HS/LS configurations of the crystal and to the assessment of the experimental (P,T) phase diagram. (Maximum 200 words). OPEN ACCESS Int. J. Mol. Sci. 2014, 15 2

Isoelectronic with CrO2, CrNF isproposed in silico based on rutile derived structure swith DFT computations. The ground state structure defined from cohesive energies is of MgUO4-type, characterized by short covalen tCr–N and long ionic Cr–F distances. Like CrO2 it is a half-metallic ferromagnet with M= 2 μB/FU intege rmagnetization with reduced band gap at minority spins . Major difference of magnetic response to pressure characterizes CrNF as a soft ferromagnet versus hard magnetic CrO2.
The chemical bonding properties point to prevailing covalent Cr–N versus ionic Cr–F bonding. Different
synthesis routes are examined.

The intermetallic magnesium compounds LaMgX and CeMgX (X = Ga, In, Tl, Pd, Ag, Pt, Au) crystallize with the hexagonal ZrNiAl type structure, space group  , with full Mg–X ordering. From density functional theory calculations carried out exem-plarily on four representative compounds: LaMgX and CeMgX with X = Ga, Pd, signifi-cant differences were traced out as to the magnetism arising only for the Ce series lead-ing to identify CeMgGa as an antiferromagnet in its ground state, in agreement with ex-periment. The bulk module magnitudes show the trend of harder transition metal based ternaries and the cohesive energies favor the X = Pd compounds versus X = Ga ones. Such features were clarified by examining the properties of chemical bonding which exhibit more directional bonds thanks to the Pd d states. Rationalizing the trends of charge transfers, negatively charged triel and transition element atoms are observed. The resulting chemical pictures assign these compounds as gallides and palladides.

We investigate light-induced excited spin-state trapping (LIESST) dynamics of an FeIII spin-crossover material from low (S=1/2) to high (S=5/2) spin states. Our results show that this process occurs only at the molecular level as evidenced by the linear dependence of the fraction of photo-switched molecules with the excitation density as well as with the initial fraction of low spin molecules. The inter-system crossing from photoexcited LS (S=1/2) to HS (S=5/2) occurs within 200 fs and is accompanied by coherent non-equilibrium vibrational relaxation in the photo-induced HS state. These results reveal similar dynamical features to those already reported for LIESST in FeII systems. The activation of coherent molecular vibrations is essential for reaching rapidly the HS potential on the timescale of molecular motions, whereas their fast damping allows an efficient trapping in the HS potential. The observed coherent oscillations are attributed to photoinduced molecules in the HS state...

We investigate light-induced excited spin-state trapping (LIESST) dynamics of an FeIII spin-crossover material from low (S=1/2) to high (S=5/2) spin states. Our results show that this process occurs only at the molecular level as evidenced by the linear dependence of the fraction of photo-switched molecules with the excitation density as well as with the initial fraction of low spin molecules. The inter-system crossing from photoexcited LS (S=1/2) to HS (S=5/2) occurs within 200 fs and is accompanied by coherent non-equilibrium vibrational relaxation in the photo-induced HS state. These results reveal similar dynamical features to those already reported for LIESST in FeII systems. The activation of coherent molecular vibrations is essential for reaching rapidly the HS potential on the timescale of molecular motions, whereas their fast damping allows an efficient trapping in the HS potential. The observed coherent oscillations are attributed to photoinduced molecules in the HS state...

The electronic and magnetic properties of the nitrides Fe2N and hypothetical FeN were investigated by use of the ASW method. For both nitrides, the calculations were done in the orthorhombic structure of Fe2N for the two nitrides. The magnetization is low (0.95μB/at.) for Fe2N and vanishes for FeN. The decrease of the magnetization with increasing amount of N is assessed within the Fe-N system in a model derived from a Slater-Pauling type behavior. Accordingly, a trend from weak to strong ferromagnetism is suggested.

PACS 71.20.-b-Electron density of states and band structure of crystalline solids PACS 71.27.+a-Strongly correlated electron systems; heavy fermions PACS 75.20.Hr-Local moment in compounds and alloys; Kondo effect, valence fluctuations, heavy fermions Abstract-Applying density functional theory within the generalized gradient approximation, we investigate the electronic and magnetic properties of the intermetallic rare-earth system Yb3Pt4. This material recently has been put forward as host for quantum criticality, while details of the magnetic ordering could not be established (Bennett N. C. et al., J. Magn. & Magn. Mater., 321 (2009) 2021). In this context, we investigate the effect of spin-orbit coupling and compare various spin patterns from the energetic point of view, which enables us to determine the electronic ground state of Yb3Pt4. The assumption of an elementary superexchange mechanism yields a magneticcoupling constant in good agreement with the experimental ordering temperature.

Gradual hydrogen uptake into Zr 2 Cu intermetallic leads to crystal symmetry changes from tetragonal Zr 2 CuH 2 to monoclinic Zr 2 CuH 5. This experimental finding is explained here from cohesive energies computed within quantum DFT for Zr 2 CuH x (x ¼ 1, 2, 3, 4, 5) models in both structures. The threshold is found at 2 < x < 3 in agreement with experiment. Beside structural crossover, electronic properties, chemical bonding, and mechanical behavior are also analyzed. MetaleH interactions arising from increasingly H presence in Zr 2 Cu lead to more and most cohesive and harder Zr 2 CuH 2 and Zr 2 CuH 5 respectively.

Based on DFT energy discrimination and detailed electronic and bonding properties, it is shown that the hitherto unexplored cerium nitride fluoride can be obtained in rhombohedral ThNF structure whereas actual CeNCl is confirmed in the early determination PbFCl-like structure. The respectively adopted 3D and 2D like structures are assigned to the major role played by the F polarizability, four times smaller than Cl. In their ground state both compound are found small gap insulators with 1.9 eV (CeNCl), 1.8 eV (CeNF) compared to insulating isoelectronic cerine CeO2 with 2.2 eV band gap. The bonding shows balance between covalence brought by Ce-N bond versus ionic Ce-F(Cl) bonding and d(Ce-N) < d(Ce-F(Cl)) distances. Synthesis routes for CeNF are proposed.

A study at both the molecular and extended solid level in the framework DFT is carried out for KM[Cr(CN)6] (M = V, Ni). From molecular calculations, the exchange parameters J are obtained, pointing to the expected magnetic ground states, i.e., antiferromagnetic for M = V with J =-296.5 cm −1 and ferromagnetic for M = Ni with J = +40.5 cm −1. From solid state computations the same ground states and J magnitudes are confirmed from energy differences. Furthermore an analysis of the site projected density of states and of the chemical bonding is developed in which the cyanide ion linkage is analyzed addressing some isomerism aspects.

Band theoretical results are presented on UO 2 CO 3 , based on computations within the density functional theory. The equation of state is obtained with equilibrium lattice properties in agreement with experiment. For isotropic volume change the bulk modulus amounts to 176 GPa. A higher value for anisotropic compression along the linear uranyl characterizes its incompressibility. The electronic band structure shows a semiconducting behavior (∼2 eV band gap) with little band dispersion. From chemical bonding plots and electron localization function mapping, oxygen atoms are found to preferentially bind with uranium for one sublattice and to carbon forming the carbonate ions for the 2 others. This further illustrates the ionic-like (UO 2) 2+ (CO 3) 2− chemical picture.

The dinitrides CN 2 , SiN 2 , and GeN 2 in assumed pyrite-type structures are studied by means of density functional theory using both ultrasoft pseudopotentials and the augmented spherical wave (ASW) method. The former two materials constitute the large-x limit of the broader class of CN x and SiN x compounds, which are well known for their interesting mechanical and electronic properties. For CN 2 a large bulk modulus B 0 of 405 GPa was determined. While SiN 2 is found to be a wide band gap compound, the calculated gaps of CN 2 and GeN 2 are considerably smaller. The trends in structural and electronic properties as e.g. bond lengths, band gaps and covalency are well understood in terms of the interplay of different types of bonding.

From DFT based calculations establishing energy-volume equations of state, a proposition of high pressure candidate structures with reduced volumes, namely columbite and trirutile are proposed for fordite mineral SnNb 2 O 6. The key effect is the destabilization of divalent tin in fordite towards tetravalent state upon compression. This is helped with smaller size tetravalent tin. The remarkable electronic structure change is the transformation from semiconducting fordite to metallic high pressure forms thanks to the electron transfer from Sn to Nb and O as quantified from charge density analyses.

The overall large ionic character of MgH 2 is reduced by inserting light elements from the first period, B and C, using a trirutile host superstructure. Both elements are found destabilizing to the structure with largely positive cohesive energy with interstitial B and slightly negative cohesive energy with interstitial C. This trend is also observed for low amounts of insertion down to (B,C) 0.167 MgH 2. From the Bader charge analysis the largely ionic character of hydrogen is decreased to an average H-0.37 in the neighborhood of C and H-0.75 for the other hydrogen atoms atoms (resp. H-0.64 and H-0.76 for B insertion). This peculiar behavior should enable enhancing the kinetics of H release for potential applications. Light elements-induced iono-covalent character in MgH 2 : an ab-initio approach.