Search results for "tetrahedron"
showing 5 items of 75 documents
Mechanism of aluminium incorporation into C–S–H from ab initio calculations
2014
Blended cements have great potential to reduce the CO2 footprint due to cement production. C(alcium)–S(ilicate)–H(ydrate) in these novel materials is known to incorporate a considerable amount of Al. We have for the first time applied large-scale first principles calculations to address the mechanism of Al incorporation into low C/S ratio C–S–H. In agreement with state-of-the-art NMR information, our calculations show that Al substitutes Si in bridging tetrahedra only, and that substitutions in pairing tetrahedra are strongly disfavoured in a wide range of conditions. In broad terms, the energy penalty for having an Al atom in a pairing position is of about 20 kcal mol−1. Al in bridging tet…
Sterically controlled self-assembly of tetrahedral M(6)L(4) cages via cationic N-donor ligands.
2014
Tripodal cationic N-donor ligands exhibit sterically controlled self-assembly of tetrahedral M6L4 coordination cages that promote selective anion encapsulation (PF6(-)OTf(-)) in the solid state. The described method is a potential template for stepwise assembly of hetero-ligand coordination cages and polymers.
White Phosphorus Is Air-Stable Within a Self-Assembled Tetrahedral Capsule
2009
Molecular Fire Quencher Cage-shaped molecular assemblies can regulate the reactivity of smaller molecules trapped within them. Mal et al. (p. 1697 ) extend this approach to enable the protection of elemental white phosphorus (P 4 ), a substance that rapidly ignites on contact with oxygen. The tetrahedral cages self-assemble in aqueous solution through coordination of six ligands to four iron ions, and efficiently capture phosphorus from a suspension. The water-soluble host-guest constructs were stable in air for at least 4 months, but released intact P 4 rapidly on displacement by added benzene.
The SO2F2 quasi-spherical top: Correspondence between tensorial and Watson's formalisms
2006
Abstract The SO2F2 quasi-spherical top molecule with C2v symmetry is considered as a distorted spherical top deriving from the SO 4 2 − tetrahedral ion. We present here a detailed correspondence between the tensorial formalism using the Td⊃C2v reorientation and the usual Hamiltonian of Watson. We have also performed ab initio calculations in order to determine the centrifugal distorsion constants in the vibrational ground state.
The N-dimensional N-person chesslike game strategy analysis model
2016
In this research a mathematical, symmetric n-player game model, based on chess is designed. Symmetry in this context refers to players' positions with respect to each other. While the order of move naturally violates the symmetry, this problem may also be solved. The motivation for building this kind of game model stems from the difficulty of finding mathematical solutions for multi-player games in general. The number of varying factors is so huge, that finding optimal strategies is mathematically almost impossible. The best way to attempt this is to use simulation. Once the model has been built, it can be applied in many ways by using computational algorithms based on the created model. Ch…