The existence of the cubic perovskite phase SnTaO3 has been confirmed by using the bond valence model. The bond valence analysis of the crystal structure of SnTaO3 involved (i) evaluating the reliability of the bond valence parameters reported earlier for Sn(II)—O bonds; (ii) determining the hitherto unreported bond valence parameters for Ta(IV)—O bonds; (iii) calculating the bond valence sums ...

Quantum spin-lattice systems in low dimensions exhibit a variety of interesting zero-temperature phases, some of which show non-classical (i.e., non-magnetic) long-range orders, such as dimer or trimer valence-bond order. These symmetry-breaking systems with localized valence bonds are referred to as valence-bond lattices (VBL) in this article. A review of our systematic microscopic formalism b...

We present a large-N variational approach to describe the magnetism of insulating doped semiconductors based on a disorder-generalization of the resonating-valence-bond theory for quantum antiferromagnets. This method captures all the qualitative and even quantitative predictions of the strong-disorder renormalization group approach over the entire experimentally relevant temperature range. Fin...

Generalized valence bond plus configuration interaction calculations have been carried out on the monopositive diatomic metal hydride ions of the second transition-metal series (YH+-CdH+, including SrH'). We analyze the trends in bond energies, equilibrium geometries, vibrational frequencies, and metal orbital hybridizations. The trends in these quantities can be understood in terms of (1) the ...

The concept of green hydropower needs an evaluation procedure for the ecological upgrading of hydropower plants based on scientific criteria [1]. For the planning and evaluation of riverrestoration programs, concepts like “ecosystem integrity” or “river health” have been proposed and empirically tested. Computer programs have been developed, which allow the testing of alternative restoration co...

Computer programs may go wrong due to exceptional behaviors, out-of-bound array accesses, or simply coding errors. Thus, they cannot be blindly trusted. Scientific computing programs make no exception in that respect, and even bring specific accuracy issues due to their massive use of floating-point computations. Yet, it is uncommon to guarantee their correctness. Indeed, we had to extend exist...

Incorporating the tight-binding theory and the bond order-length-strength (BOLS) correlation into the X-ray photoelectron spectra of Ag(111) and (100) surfaces and the Auger electron spectra of Ag nanoparticles deposited on Al2O3 and CeO2 substrates has led to quantitative information of the 3d5/2 and the valence binding energies of an isolated Ag atom and their shifts upon bulk, defect, surfac...

cycloaddition reaction between c30 and hula-i, 3-diene was studied within the snimework of am i (rhf)level. the reaction involving the double bond between two hexagons and a hexagon and a pentagon, as wellas the cycloaddition products followed by disrotatory ogs s electrocyclic ring openings were considered.thermodynamics parameters and stability energy and innsation state are evaluated in thre...