scholarly journals Combined DFT and XPS Investigation of Cysteine Adsorption on the Pyrite (1 0 0) Surface

Minerals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 366 ◽  
Author(s):  
Xingfu Zheng ◽  
Xuan Pan ◽  
Zhenyuan Nie ◽  
Yi Yang ◽  
Lizhu Liu ◽  
...  
Keyword(s):  
First Principles ◽  
Photoelectron Spectroscopy ◽  
Density Functional ◽  
Interaction Mechanism ◽  
Energy Calculation ◽  
Ionic Bond ◽  
Frontier Orbitals ◽  
Functional Theory ◽  
Xps Spectra ◽  
X Ray

The adsorption of cysteine on the pyrite (1 0 0) surface was evaluated by using first-principles-based density functional theory (DFT) and X-ray photoelectron spectroscopy (XPS) measurements. The frontier orbitals analyses indicate that the interaction of cysteine and pyrite mainly occurs between HOMO of cysteine and LUMO of pyrite. The adsorption energy calculation shows that the configuration of the -OH of -COOH adsorbed on the Fe site is the thermodynamically preferred adsorption configuration, and it is the strongest ionic bond according to the Mulliken bond populations. As for Fe site mode, the electrons are found transferred from cysteine to Fe of pyrite (1 0 0) surface, while there is little or no electron transfer for S site mode. Projected density of states (PDOS) is analyzed further in order to clarify the interaction mechanism between cysteine and the pyrite (1 0 0) surface. After that, the presence of cysteine adsorption on the pyrite (1 0 0) surface is indicated by the qualitative results of the XPS spectra. This study provides an alternative way to enhance the knowledge of microbe–mineral interactions and find a route to improve the rate of bioleaching.

The Mechanism Research of Collector and Hemimorphite

2014 ◽  
Vol 1073-1076 ◽  
pp. 2163-2167
Author(s):  
Kang Kang Li ◽  
Xiao Lin Zhang ◽  
Shi Ming Cao ◽  
Dian Wen Liu
Keyword(s):  
Zinc Oxide ◽  
Photoelectron Spectroscopy ◽  
Density Functional ◽  
Adsorption Mechanism ◽  
Efficient Utilization ◽  
Functional Theory ◽  
X Ray ◽  
The Density Functional Theory ◽  
Mechanism Research ◽  
Drying Up

As the zinc minerals of easy separation drying up, efficient utilization of refractory zinc oxide ores is getting more and more attention, especially for siliceous zinc oxide ore is quite difficult to separate, and it is a challenge for worldwide mineral processing industry. This article mainly used the density functional theory and X-ray photoelectron spectroscopy to study the adsorption mechanism of amine collectors on hemimorphite, when the composite activator was working.

Experimental and First-Principles Studies of the Band Alignment at the HfO2/4H-SiC (0001) Interface

2006 ◽  
Vol 527-529 ◽  
pp. 1071-1074 ◽  
Author(s):  
Carey M. Tanner ◽  
Jong Woo Choi ◽  
Jane P. Chang
Keyword(s):  
Conduction Band ◽  
Photoelectron Spectroscopy ◽  
Density Functional ◽  
Atomic Layer ◽  
Band Alignment ◽  
Functional Theory ◽  
X Ray ◽  
Conduction Band Offset ◽  
Mos Devices ◽  
Layer Deposition

The electronic properties of HfO2 films on 4H-SiC were investigated to determine their suitability as high-κ dielectrics in SiC power MOS devices. The band alignment at the HfO2/4HSiC interface was determined by X-ray photoelectron spectroscopy (XPS) and supported by density functional theory (DFT) calculations. For the experimental study, HfO2 films were deposited on ntype 4H-SiC by atomic layer deposition (ALD). XPS analysis yielded valence and conduction band offsets of 1.69 eV and 0.75 eV, respectively. DFT predictions based on two monoclinic HfO2/4HSiC (0001) structures agree well with this result. The small conduction band offset suggests the potential need for further interface engineering and/or a buffer layer to minimize electron injection into the gate oxide.

THE Ge(001) SURFACE RECONSTRUCTION: DFT AND MCS

1999 ◽  
Vol 06 (06) ◽  
pp. 1045-1051 ◽  
Author(s):  
YOSHIHIDE YOSHIMOTO ◽  
YOSHIMICHI NAKAMURA ◽  
HIROSHI KAWAI ◽  
MASARU TSUKADA ◽  
MASATOSHI NAKAYAMA
Keyword(s):  
Phase Transition ◽  
First Principles ◽  
Density Functional ◽  
First Principles Calculation ◽  
Transient Temperature ◽  
Diffraction Experiment ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
Flip Flop ◽  
X Ray

The problem of relative energetic stabilities of the high order reconstructions of the Ge(001) surface is revisited by a more refined first-principles calculation based on density functional theory. Using this result, we performed a Monte Carlo simulation of the phase transition, and obtained 315 K as the transition temperature of p(2× 1) → c(4× 2). This reproduces fairly well the transient temperature (250–350 K) observed by an X-ray diffraction experiment. The obtained geometry of the c(4× 2) structure compares well with an X-ray diffraction experiment. The potential energy curves of flip-flop motions of both single dimer and dimer in type-P defect are also obtained.

scholarly journals Operando XANES from first-principles and its application to iridium oxide

2020 ◽  
Vol 22 (19) ◽  
pp. 10807-10818 ◽  
Author(s):  
Francesco Nattino ◽  
Nicola Marzari
Keyword(s):  
Density Functional Theory ◽  
Absorption Spectra ◽  
First Principles ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Applied Potential ◽  
Functional Theory ◽  
X Ray ◽  
Continuum Description ◽  
X Ray Absorption

Density-functional theory calculations augmented with a continuum description of the electrochemical environment are implemented to simulated X-ray absorption spectra as a function of the applied potential.

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