Investigation of CO Adsorption on Hydroxyapatite (001) Surface Using Density Functional Theory

2021 ◽  
Vol 1028 ◽  
pp. 215-220
Author(s):  
Liza Saharani Hamzah ◽  
Juliandri ◽  
Atiek Rostika Noviyanti ◽  
Budi Adiperdana ◽  
Risdiana

Hydroxyapatite (HA) is a phosphate mineral with the chemical formula of Ca10(PO4)6(OH)2. The presence of pores in HA allows easy interaction with other compounds, so it can be used to detect the CO gas. Other than that, the hydroxyl group in hydroxyapatite allows the ion exchange process, a significant reaction in a gas sensor. The interaction of hydroxyapatite with CO gas has been studied using density functional theory. The HA adsorption potential energy surface was investigated using slab model with (001) expansion and 10 Å vacuum. CO gas kept fixed 1.0 Å above the HA surface and traced along the surface with grid 10×10. The result shows that the surface is divided into two main potentials that more likely and unlikely for CO to stay. The CO gas is most likely to stay between two oxygen from (PO3) tetrahedral that pointing down.

2007 ◽  
Vol 06 (03) ◽  
pp. 549-562
Author(s):  
ABRAHAM F. JALBOUT

The transition states for the H 2 NO decomposition and rearrangements mechanisms have been explored by the CBS-Q method or by density functional theory. Six transition states were located on the potential energy surface, which were explored with the Quadratic Complete Basis Set (CBS-Q) and Becke's one-parameter density functional hybrid methods. Interesting deviations between the CBS-Q results and the B1LYP density functional theory lead us to believe that further study into this system is necessary. In the efforts to further assess the stabilities of the transition states, bond order calculations were performed to measure the strength of the bonds in the transition state.


2013 ◽  
Vol 12 (05) ◽  
pp. 1350035 ◽  
Author(s):  
LIXIA YANG ◽  
XIAOLI LEI ◽  
JUN FENG ◽  
YUXIN ZHANG ◽  
MINGXING LIU

Comparative study about the adsorption and dissociation behaviors of H2O molecule on clean and vacancy defective Al (111) surface was conducted by extensive density functional theory (DFT) calculations, the interaction mechanisms between H2O molecule and Al (111) surface were also figured out. Geometry optimization results indicated that H2O molecule was apt to be adsorbed at top site on these two kinds of surfaces, whereas, the adsorption configurations, the adsorption type and inclination of H2O molecule planes away from the normal were different. The calculated adsorption energies demonstrated that the adsorption of H2O molecule occurred more readily on vacancy defective Al (111) surface. The electron density distribution indicated that the vacancy defect enhanced the interactions between H2O molecule and surface Al atoms. Further analysis of the density of states (DOS) showed that the vacancy defect increased the number of bonding electrons between H2O molecule and surface Al atoms. The detailed exploration of dissociation pathways demonstrated that the dissociation of H2O molecule on these two kinds of surfaces was a two-step process: (1) H2O → H + OH , (2) OH → H + O . However, for each step the dissociation pathway variations on vacancy defective Al (111) surface were different with those on clean Al (111) surface. Compared with the first step, the dissociation of hydroxyl group into O atom and H atom was kinetically difficult. The calculated lower activation energy barriers on vacancy defective Al (111) surface showed that the vacancy defect had catalytic effect for the dissociation of H2O molecule to some extent, especially for the first step.


RSC Advances ◽  
2019 ◽  
Vol 9 (34) ◽  
pp. 19657-19661 ◽  
Author(s):  
Gwladys Steciuk ◽  
Seyedayat Ghazisaeed ◽  
Boris Kiefer ◽  
Jakub Plášil

The crystal structure of the U(iv)-phosphate mineral vyacheslavite has been solved from precession electron diffraction tomography (PEDT) data from the natural nano-crystal and further refined using density-functional theory (DFT) calculations.


2019 ◽  
Vol 21 (21) ◽  
pp. 10888-10894
Author(s):  
Jorge Ontaneda ◽  
Francesc Viñes ◽  
Francesc Illas ◽  
Ricardo Grau-Crespo

Density functional theory calculations with non-local correlation functionals, properly accounting for dispersion forces, predict the presence of two minima in the interaction energy between h-BN and Ni(111).


2017 ◽  
Vol 70 (4) ◽  
pp. 362 ◽  
Author(s):  
Young J. Hong ◽  
Dean J. Tantillo

An energetically viable (on the basis of results from density functional theory computations) pathway to the diterpene variediene is described. Only one of the three secondary carbocations along this pathway is predicted to be a minimum on the potential energy surface.


2004 ◽  
Vol 823 ◽  
Author(s):  
Jun Feng ◽  
Yong-Hyun Kim ◽  
S. B. Zhang ◽  
Shi-You Ding ◽  
Melvin P. Tucker ◽  
...  

AbstractChemical action between cyclodextrins (CDs) and TOPO-(CdSe)ZnS quantum dots (QDs) generates a water-soluble solution of CD-QDs. Hydrophobic TOPO molecules on surface of the QDs are compatible to thread through the pockets of CDs and make the hydroxyl group on end of CDs to approach the ZnS surface, and then cause the interaction between ZnS and the hydroxyls. In this paper, Photoluminescence of the γ-CD-QD solution appeared about 15 nm of red movement compared with that of the QDs in hexane; 58% replacement of the crystal coordinate bond of Zn-S with that of Zn-O in the ZnS shell was demonstrated by using first-principles density functional theory and the red shift of the photoluminescence of CD-QDs; and –0.11eV of the energy gain of the exchange model was calculated by using an effective mass (EM) model. CD-QDs will provide water-soluble QDs with conjugational group for biology and molecule-device applications.


2019 ◽  
Vol 21 (1) ◽  
pp. 409-417 ◽  
Author(s):  
Daniel C. Elton ◽  
Michelle Fritz ◽  
Marivi Fernández-Serra

We present a new approximate method for doing path integral molecular dynamics simulation with density functional theory and show the utility of the method for liquid water.


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