Understanding the stability and reactivity of iron sulfide phases is key to developing predictive capabilities for assessing their corrosion and catalytic activity. The differences between the free surface and the bulk interior of such phases are of particular importance in this context. Here, we employ density functional theory to investigate the formation energetics and electronic structure o...

We present the results of calculations of surface relaxations, rumplings, energetics, optical band gaps, and charge distribution for the SrZrO(3) and PbZrO(3) (001) and (011) surfaces using the ab initio code CRYSTAL and a hybrid description of exchange and correlation. We consider both SrO(PbO) and ZrO(2) terminations of the (001) surface and Sr(Pb), ZrO, and O terminations of the polar SrZrO(...

We report high resolution state-to-state time-of-flight (TOF) measurements for scattering of HCl(v=2, J=1) from a Au(111) single crystal surface for both vibrationally elastic (v=2-->2) as well as inelastic (v=2-->1) channels at seven incidence energies between 0.28 and 1.27 eV. The dependences of the TOF results on final HCl rotational state and surface temperature are also reported. The trans...

Hydrates in some crude oils have a smaller tendency to form plugs than in others, and lately this is becoming a focus of research. To study this and the action of hydrate antiagglomerants in general, hydrate surface properties must be known. To help in characterizing the surface properties by simulation, the capillary waves of clathrate hydrate surfaces in vacuum is examined in all unique cryst...

Electronegativity is a fundamental concept in chemistry. Despite its importance, the experimental determination has been limited only to ensemble-averaged techniques. Here, we report a methodology to evaluate the electronegativity of individual surface atoms by atomic force microscopy. By measuring bond energies on the surface atoms using different tips, we find characteristic linear relations ...

Using supersonic molecular beam techniques we have investigated the dissociative adsorption of NH3 on a Ru~0001! surface. At high incident energies, the dissociation increases substantially due to a direct breaking of the N–H bond on impact with the surface. For low incident translational energies, the dissociation depends on surface temperature Ts in an unusual manner, peaking sharply around 4...

A first-principles model of the electrochemical double layer is applied to study surface energies and surface coverage under realistic electrochemical conditions and to determine the equilibrium shape of metal nanoparticles as a function of applied potential. The potential bias is directly controlled by adding electronic charge to the system, while total energy calculations and thermodynamic re...

the adsorption of a number of amino acids on a defected single-walled carbon nanotube (swcnt) isinvestigated by using the density-functional theory (dft) calculations. the adsorption energies andequilibrium distances are calculated for various configurations such as amino acid attaching to defectsites heptagon, pentagon and hexagon in defective tube and also for several molecular orientationswi...

We determine potentials of the mean force for interactions of amino acids with four common surfaces of ZnO in aqueous solutions. The method involves all-atom molecular dynamics simulations combined with the umbrella sampling technique. The profiled nature of the density of water with the strongly adsorbed first layer affects the approach of amino acids to the surface and generates either repuls...

In this research. CO gas molthules were approached to single-wall carbon nanotube (SWNT) and (6,0) CNTsurface from carbon side and oxygen side in three states (top, bridge, centre) and two shapes ( erlica I.horizontal), then adsorption energies were calculated by B3TYP/6-310 B3LYPI3-216" and Hge3-210"methods after that they were compared m order to obtain the most stable adsorption state. OFT a...