EXPERIMENTAL AND THEORETICAL STUDIES OF BINDING INTERACTIONSIN DIVALENT TRANSITION METAL CATION-N-DONOR LIGANDCOMPLEXES: STRUCTURES, SEQUENTIAL BOND DISSOCIATION ENERGIES,MECHANISMS AND ENERGETICS OF COLLISION-INDUCED DISSOCIATION

Background and Aim: Preparation of tooth structure by laser systems produces a surface with different characteristics. Therefore, selecting an appropriate bonding system is necessary to achieve the maximum bond strength. The aim of this study was to compare the bond strength of Adper Single Bond 2 adhesive and Single Bond Univer-sal to dentin prepared by bur or laser. Materials and Methods: ...

A new method for constructing empirical valence bond potential energy surfaces for reactions is presented. Building on the generalized Gaussian approach of Chang-Miller, V12(2)(q) is represented by a Gaussian times a polynomial at the transition state and generalized to handle any number of data points on the potential energy surface. The method is applied to two model surfaces and the HCN isom...

AIM The aim of this in vitro study was to evaluate and compare the shear bond strength of teeth reattached with sixth generation dentin bonding agent: Xeno III and microhybrid resin composite: Esthet-X, using three different techniques: (1) Simple reattachment, (2) overcontour and (3) internal dentinal groove. METHODOLOGY A total of 70 human maxillary central incisors were selected and divide...

The nature of chemical bonds on dynamic paths was investigated using the complete active space valence-bond (CASVB) method and the Born-Oppenheimer dynamics. To extract the chemical bond picture during reactions, a scheme to collect contributions from several VB (resonance) structures into a small numbers of indices was introduced. In this scheme, a tree diagram for the VB structures is constru...

Atomic structures, energies, and stress distributions of symmetrical ^011& tilt grain boundaries ~GB’s! and selected GB triple junctions ~TJ’s! in diamond as well as a multiply twinned diamond particle have been calculated using an analytic bond order potential function. In general, energies of ^011& tilt GB’s are about 1 J/m lower than those for ^001& tilt GB’s calculated with the same analyti...

A molecule is formed by the combination of atoms and in the process they attain the electronic configuration of an inert gas. A chemical bond is formed as a result of attraction between the combining atoms. To explain the formation of bonds in diatomic molecules, such as H2, O2, N2, Cl2 etc., it was first suggested by G.N. Lewis that atoms of such molecules attain an inert gas electronic config...

Internal coordinates such as bond lengths, bond angles, and torsion angles (BAT) are natural coordinates for describing a bonded molecular system. However, the molecular dynamics (MD) simulation methods that are widely used for proteins, DNA, and polymers are based on Cartesian coordinates owing to the mathematical simplicity of the equations of motion. However, constraints are often needed wit...