skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: First-principles study of water adsorption on α-SiO{sub 2} [110] surface

Abstract

We have investigated the structural and electronic properties of water molecule adsorbed silicon dioxide (α-SiO{sub 2}) [110] surface and analyzed the influence of water molecule on its energetics, structure and electronic properties using density functional theory based first principles calculations. The inhomogeneous topology of the α-SiO{sub 2} clean surface promotes a total charge density displacement on the adsorbed water molecule and giving rise to electron-rich as well as hole-rich region. The electronic charge transfer from a α-SiO{sub 2} to the water molecule occurs upon the formation of a partially occupied level laying above conduction band level.

Authors:
 [1];  [2]
  1. Department of Physics, MK Bhavnagar University, Bhavnagar-364001 (India)
  2. Department of Physics, Faculty of Science, the M.S. University of Baroda, Vadodara-390 002 (India)
Publication Date:
OSTI Identifier:
22611434
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 6; Journal Issue: 8; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ADSORPTION; AMORPHOUS STATE; CHARGE DENSITY; COMPUTERIZED SIMULATION; DENSITY; DENSITY FUNCTIONAL METHOD; MOLECULES; SILICON; SILICON OXIDES; SURFACES; WATER

Citation Formats

Mankad, Venu, and Jha, Prafulla K., E-mail: prafullaj@yahoo.com. First-principles study of water adsorption on α-SiO{sub 2} [110] surface. United States: N. p., 2016. Web. doi:10.1063/1.4960455.
Mankad, Venu, & Jha, Prafulla K., E-mail: prafullaj@yahoo.com. First-principles study of water adsorption on α-SiO{sub 2} [110] surface. United States. doi:10.1063/1.4960455.
Mankad, Venu, and Jha, Prafulla K., E-mail: prafullaj@yahoo.com. 2016. "First-principles study of water adsorption on α-SiO{sub 2} [110] surface". United States. doi:10.1063/1.4960455.
@article{osti_22611434,
title = {First-principles study of water adsorption on α-SiO{sub 2} [110] surface},
author = {Mankad, Venu and Jha, Prafulla K., E-mail: prafullaj@yahoo.com},
abstractNote = {We have investigated the structural and electronic properties of water molecule adsorbed silicon dioxide (α-SiO{sub 2}) [110] surface and analyzed the influence of water molecule on its energetics, structure and electronic properties using density functional theory based first principles calculations. The inhomogeneous topology of the α-SiO{sub 2} clean surface promotes a total charge density displacement on the adsorbed water molecule and giving rise to electron-rich as well as hole-rich region. The electronic charge transfer from a α-SiO{sub 2} to the water molecule occurs upon the formation of a partially occupied level laying above conduction band level.},
doi = {10.1063/1.4960455},
journal = {AIP Advances},
number = 8,
volume = 6,
place = {United States},
year = 2016,
month = 8
}
  • Long-chain alkanoic acids usually form close-packed monolayer films with alkyl chains highly oriented on substrates. Previous studies have reported the adsorption of stearic acid on gold, aluminum, copper, silver, and aluminum oxide. However, there are no reports of stearic acid adsorption on magnetic metals. In this work, the characterization of stearic acid adsorbed on Ni(111) surface has been studied experimentally and with first-principles calculation. The results suggest that the stearic acid is chemically adsorbed on the Ni(111) surface via a bidentate interaction with a distance of about 1.8 A. Besides this, we have also obtained results for the charge transfermore » and magnetic proximity effect.« less
  • First-principles calculations are performed to study the energetics and atomic structures of aluminum adsorption and incorporation at clean and Ga-bilayer GaN(0001) surfaces. We find the favorable adsorption site changes from T4 to T1 as Al coverage increased to 1 monolayer on the clean GaN(0001) surface, and a two-dimensional hexagonal structure of Al overlayer appears. It is interesting the Al atoms both prefer to concentrate in one deeper Ga layer of clean and Ga-bilayer GaN(0001) surface, respectively, while different structures could be achieved in above surfaces. For the case of clean GaN(0001) surface, corresponding to N-rich and moderately Ga-rich conditions, amore » highly regular superlattice structure composed of wurtzite GaN and AlN becomes favorable. For the case of Ga-bilayer GaN(0001) surface, corresponding to extremely Ga-rich conditions, the Ga bilayer is found to be sustained stable in Al incorporating process, leading to an incommensurate structure directly. Furthermore, our calculations provide an explanation for the spontaneous formation of ordered structure and incommensurate structure observed in growing AlGaN films. The calculated results are attractive for further development of growth techniques and excellent AlGaN/GaN heterostructure electronic devices.« less
  • Experimental studies of nitriding on uranium surfaces show that the modified layers provide considerable protection against air corrosion. The bimodal distribution of nitrogen is affected by both its implantation and diffusion, and the diffusion of nitrogen during implantation is also governed by vacancy trapping. In the present paper, nitrogen adsorption, absorption, diffusion, and vacancy trapping on the surface of and in the bulk of α–uranium are studied with a first-principles density functional theory approach and the climbing image nudged elastic band method. The calculated results indicate that, regardless of the nitrogen coverage, a nitrogen atom prefers to reside at themore » hollow1 site and octahedral (Oct) site on and below the surface, respectively. The lowest energy barriers for on-surface and penetration diffusion occur at a coverage of 1/2 monolayer. A nitrogen atom prefers to occupy the Oct site in bulk α–uranium. High energy barriers are observed during the diffusion between neighboring Oct sites. A vacancy can capture its nearby interstitial nitrogen atom with a low energy barrier, providing a significant attractive nitrogen-vacancy interaction at the trapping center site. This study provides a reference for understanding the nitriding process on uranium surfaces.« less
  • ZnO has been actively studied for potential usage as a transparent conducting oxide (TCO) for a variety of applications including organic light emitting diodes and solar cells. In these applications, fine-tuning the workfunction of ZnO is critical for controlling interfacial barriers and improving the charge injection (or outcoupling) efficiencies. We have performed plane wave periodic density functional theory calculations to investigate the effect of different surface absorbents and surface defects (including surface non-stoichiometry) on the workfunction of ZnO. The aim was to understand the underlying mechanism of workfunction changes, in order to engineer specific workfunction modifications. Accurate calculations of workfunctionsmore » of polar surfaces were achieved by introducing balancing pseudo charges on one side of the surface to remove the dipolar effect. It was found that increasing the surface coverage of hydrocarbons (-CH{sub 3}) decreased the workfunction, while adsorption of highly electronegative-F and -CF{sub 3} groups and increases in surface O/Zn ratio increased the workfunction of ZnO. The increase of workfunction was found to be directly correlated to the enhancement variation of surface dipole moment due to adsorptions or other surface modifications. Introducing surface absorbents that increase surface dipole moment can be an effective way to increase workfunction in ZnO TCOs.« less
  • The oxygen adsorption on the Zr(0001) surface is studied using first-principles total-energy and force calculations. We calculated the atomic structure, heat of adsorption, work function, and electronic structure for oxygen occupying various surface and subsurface sites for both the Zr(0001)-(1{times}1)-O and Zr(0001)- (2{times}1)-O system. We found that the energetically most favorable occupation sites for oxygen are the octahedral sites between the second and the third layer. The change in the work function induced by oxygen adsorption depends strongly on the position of the adsorbed oxygen atoms and the calculated change of work function at the energetically most favorable site ismore » consistent with previous experiments. A large difference in the electronic structure between the overlayer and subsurface adsorption is also found. {copyright} {ital 1996 The American Physical Society.}« less