We present a modified bond-valence model of PbTiO3 based on the principles of bond-valence and bond-valence vector conservation. The relationship between the bond-valence model and the bond-order potential is derived analytically in the framework of a tight-binding model. An energy term, bond-valence vector energy, is introduced into the atomistic model and the potential parameters are reoptimi...

An analytical solution shows that a competition between bond order loss and the associated bond strength gain of the lower coordinated atoms near the edge of a surface dictates the mechanics of the surface and, hence, a nanosolid. Bond order loss lowers the activation energy for atomic dislocation, whereas bond strength gain enhances the energy density or mechanical strength in the region near ...

Scanned-energy mode photoelectron diffraction results show the adsorption site of molecular water on TiO2(110) to be atop under-coordinated surface Ti atoms, confirming the results of total energy calculations and STM imaging. However, the Ti-O(water) bond length is 2.21 +/- 0.02 A, much longer than Ti-O bond lengths in strongly chemisorbed species on this surface, but significantly shorter tha...

Abstract A novel method of modeling centrifugal compression systems for surge control purposes by using bond graphs is presented. By using the bond graph method, we get a simple description of compression systems based on physical phenomena and it is straight forward to get the dynamic equations. It is demonstrated that several active surge control methods can be represented by the same bond gr...

BACKGROUND In solid state structures of organic molecules, identical sets of H-bond donor and acceptor functions can result in a range of distinct H-bond connectivity modes. Specifically, competing H-bond structures (HBSs) may differ in the quantitative proportion between one-point and multiple-point H-bond connections. For an assessment of such HBSs, the effects of their internal as well as ex...

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...

The free energy of a (1×1)-surface, with no relaxation and no adsorption, is calculated using a bond-breaking mode in which the potential energy of the crystal is treated as the sum of the energy of the bonds connecting pair-wise atoms. Based on a purely geometrical model, the number of broken bonds or dangling bonds per atom is calculated on the surface of the crystal when an atomically flat p...

The bond energies at active sites of proteins are intimately coupled to the structure-function relationship in biological systems. Due to the unknown nature of the protein relaxation along a reaction coordinate, it has not been possible to directly determine bond energies relevant to protein function. By embedding proteins in trehalose glasses, it is possible to freeze out protein relaxation on...

The characterization and applications of topological insulators depend critically on their protected surface states, which, however, can be obscured by the presence of trivial dangling bond states. Our first-principle calculations show that this is the case for the pristine (111) surface of SnTe. Yet, the predicted surface states unfold when the dangling bond states are passivated in proper che...