Search results for "Figuration"
showing 10 items of 615 documents
Reflections on the Nature of the Periodic Table of the Elements: Implications in Chemical Education
2014
The periodic table of the elements (PTE) results essential to understand our nature and place in the whole of beings. The same happens with our food, drugs, materials, etc. A series of questions were asked to introduce PTE and provide answers. The ideas in PTE should be valued by the number of questions that they generate. The PTE was related to electron configurations. The emergence of elements (nucleosynthesis) in physics was explained. The PTE results essential to understand our nature and place in the whole of beings. The same happens with our food, drugs, materials, etc. Schwarz and Rich asked a series of questions (Qs) to introduce PTE and provided answers. The ideas on PTE should be …
WITHIN-TEAM COMPETITION IN THE MINIMUM EFFORT COORDINATION GAME
2006
. We report the results of an experiment on a continuous version of the minimum effort coordination game. The introduction of within-team competition significantly increases effort levels relative to a baseline with no competition and increases coordination relative to a secure treatment where the pay-off-dominant equilibrium strategy weakly dominates all other actions. Nonetheless, within-team competition does not prevent subjects from polarizing both in the efficient and the inefficient equilibria.
Configurational landscape of chiral iron(II) bis(phosphane) complexes
2020
[EN] The reaction of a chiral [FeH(¿2-H2){(R,R)-Me-DuPhos}2]+ ((R,R)-Me-DuPhos = (¿)-1,2-bis[(2R,5R)-2,5-dimethylphospholano]benzene) complex with ethers and halides is investigated by NMR techniques. From this study, it is apparent that dihydrogen ligand exchange by poorly-coordinating donor molecules, such as THF or Et2O, is feasible under mild conditions. The cis-[FeH(THF-d8){(R,R)-Me-DuPhos}2]+ complex is identified as the product in THF-d8 solution. A mixture of cis- and trans-[FeH(ether){(R,R)-Me-DuPhos}2]+ isomers is obtained after the addition of small quantities of THF or Et2O to a CD2Cl2 solution of [FeH(¿2-H2){(R,R)-Me-DuPhos}2]+. The reaction of [FeH(¿2-H2){(R,R)-Me-DuPhos}2]+ w…
The two-dimensional iron(ii)–thiocyanate–4,4′-bipyridine coordination network
2010
The crystal structures of eight solvates of {Fe(4,4′-bipyridine)2(NCS)2}n have been determined. All of them contain a layered iron–bipyridine–thiocyanate framework formed from approximately square infinite two-dimensional (4,4) iron–bipyridine grids, with the solvent molecules hosted between adjacent layers. All the structures contain the iron(II) centres in the high-spin electronic configuration, and magnetic susceptibility measurements on the toluene and nitrobenzene solvates do not reveal any spin-crossover behaviour.
Efficient Design of Waveguide Manifold Multiplexers Based on Low-Order EM Distributed Models
2015
In this paper, a new systematic technique to design manifold-coupled multiplexers in waveguide technology is proposed. The new technique uses generalized low-order electromagnetic (EM) distributed models, which constitute a half-way point between the fast, but imprecise, analytical models, and the more accurate, but costly, full-wave EM models. The method can be applied to contiguous and noncontiguous channel multiplexers, in both E-plane or H-plane configurations. This paper covers the complete design procedure for manifold multiplexers, starting from the required specifications and finishing with the physical dimensions. After explaining the general design technique for multiplexers with …
Resolution and Determination of the Absolute Configuration of a Twisted Bis-Lactam Analogue of Tröger's Base: A Comparative Spectroscopic and Computa…
2015
The first reported twisted bis-lactam, a racemic Tröger's base (TB) analogue (2), was resolved into its enantiomers on a chiral stationary phase HPLC column. The absolute configuration of (+)-2 was determined to be (R,R)-2 by comparing experimental and calculated vibrational circular dichroism (VCD) and electronic circular dichroism (ECD) spectra. The absolute configuration of (-)-2 was determined by comparing experimental and calculated electronic circular dichroism (ECD) spectra. The corresponding theoretical spectra were calculated using the lowest energy conformation of (R,R)-2 and (S,S)-2 at the B3LYP/6-31G(d,p) level of theory. The absolute configuration of (+)-2 was also determined t…
Origin of the Paramagnetic Properties of the Mixed‐Valence Polyoxometalate [GeV 14 O 40 ] 8– Reduced by Two Electrons: Wave Function Theory and Model…
2009
The aim of the work is to give an explanation of the magnetic properties of a mixed-valence [GeV14O40]8– polyoxometalate reduced by two electrons, which, in contrast to what happens in other two-electron-reduced polyoxometalates, does not show any magnetic coupling between the two unpaired electrons. For this purpose, a quantitative evaluation of the microscopic electronic parameters (electron transfer, magnetic coupling, magnetic orbital energy, and Coulomb repulsion) of the mixed-valence polyoxometalate cluster is performed. The parameters are extracted from valence-spectroscopy large configuration interaction (CI) calculations on embedded fragments. Then, these parameters are used in an …
Full configuration interaction calculation of the low lying valence and Rydberg states of BeH
2007
The all-electron full configuration interaction (FCI) vertical excitation energies for some low lying valence and Rydberg excited states of BeH are presented in this article. A basis set of valence atomic natural orbitals has been augmented with a series of Rydberg orbitals that have been generated as centered onto the Be atom. The resulting basis set can be described as 4s2p1d/2s1p (Be/H) + 4s4p3d. It allows to calculate Rydberg states up to n= {3,4,5} of the s, p, and d series of Rydberg states. The FCI vertical ionization potential for the same basis set and geometry amounts to 8.298 eV. Other properties such as FCI electric dipole and quadrupole moments and FCI transition dipole and qua…
On the dissociation energy of Cu2 and CuH using a differential correlation approach
1990
The energy contributions involved in the “dissociation-consistent configuration interaction” (DCCI) scheme proposed by Goddard and co-workers plus the dispersion effects associated with the valence MOs adjacent to the bond (DISP) are evaluated for the Cu2 and CuH systems, following the “configuration interaction by perturbation with multiconfigurational zeroth-order wavefunction selected by iterative process” (CIPSI) algorithm. Using a relativistic pseudopotential to represent the neon core of copper, and a flexible basis set for the valence shell, the results obtained with the CIPSI/DCCI (+ DISP) approach shows a good agreement with previous theoretical results employing basis sets of simi…
A theoretical study of the electronic spectrum of thiophene
1993
Abstract The electronic spectrum of thiophene has been studied using multiconfiguration second-order perturbation theory and extended ANO basis sets. The calculations comprise four singlet valence excited states and the 3s3p3rd Rydberg series. The lowest triplet states were included and some n-π* and n-σ* states. The results have been used to assign the experimental spectrum below 8.0 eV, with a maximum deviation of about 0.1 eV for vertical transition energies. The calculations place the 2 1A1 valence state at 5.33 eV, below the 1 1B2 valence state at 5.72 eV, and the most intense valence transitions at 6.69 eV (3 1A1) and 7.32 eV (4 1B2) with oscillator strengths 0.19 and 0.39, respective…