Nano Application Material Engineering

Quantum chemistry calculations of CASSCF/CASPT2 level together with ligand field analysis are used for the investigation of magnetic anisotropy of [Mo(CN) 7 ] 4complexes. We have considered three types of heptacyano environments: two ideal geometries, a pentagonal bipyramid and a capped trigonal prism, and the heptacyanomolybdate fragment of the cyano-bridged magnetic network

Potential energy curves for the ground states for FeS and FeS À , and of several low-lying electronic states that are responsible for the FeS À photoelectron spectrum, are calculated at the CASPT2 level. Our computational approach predicts a dissociation energy D 0 = 3.13 eV and an FeS electron affinity of 1.70 eV. The ground state of FeS is 5 R + , in agreement with a previous CASSCF/ACPF study but in disagreement with a very recent investigation of the microwave spectrum. New assignments of the photoelectron spectrum of FeS À are presented.

An ab initio multiconfigurational approach has been used to calculate the ligand-field spectrum and magnetic properties of the title cyano-bridged dinuclear molybdenum complex. The rather large magnetic coupling parameter J for a single cyano bridge, as derived experimentally for this complex by susceptibility measurements, is confirmed to a high degree of accuracy by our CASPT2 calculations. Its electronic structure is rationalized in terms of spin-spin coupling between the two constituent hexacyano-monomolybdate complexes. An in-depth analysis on the basis of Anderson's kinetic exchange theory provides a qualitative picture of the calculated CASSCF antiferromagnetic ground-state eigenvector in the Mo dimer. Dynamic electron correlations as incorporated into our first-principles calculations by means of the CASPT2 method are essential to obtain quantitative agreement between theory and experiment.

A first-principles Density Functional Theory (DFT) approach was employed to predict the effective charges, phonon modes, band-gap and dielectric constant of a series of Sr-rich SrTiO 3 . The fabricated MIM capacitors confirm the theoretical trends obtained for the dielectric constants, the later showing a possible upper limit of the dielectric response.

The ground states of FeS 2 and FeS 2 -, and several low-lying excited electronic states of FeS 2 that are responsible for the FeS 2photoelectron spectrum, are calculated. At the B3LYP level an open, quasi-linear [SFeS]conformation is found as the most stable structure, which is confirmed at the ab initio CASPT2 computational level. Both the neutral and the anionic unsaturated complexes possess high-spin electronic ground states. For the first time a complete assignment of the photoelectron spectrum of FeS 2is proposed. The lowest energy band in this spectrum is ascribed to an electron detachment from the two highest-lying 3d π antibonding orbitals (with respect to the iron-sulfur bonding) of iron. The next-lowest experimental band corresponds to an electron removal from nonbonding, nearly pure sulfur orbitals. The two highest bands in the spectra are assigned as electron detachments from π and σ bonding mainly sulfur orbitals.