THE EFFECT OF H ON THE ELECTRONIC STRUCTURE OF AN Fe(110)–Pd(100) INTERFACE

2003 ◽  
Vol 10 (06) ◽  
pp. 879-888 ◽  
Author(s):  
PAULA V. JASEN ◽  
ESTELA A. GONZALEZ ◽  
OSCAR A. NAGEL ◽  
ALFREDO JUAN
Keyword(s):  
Electronic Structure ◽  
Electronic Structures ◽  
Hydrogen Permeation ◽  
Pure Metal ◽  
Detailed Knowledge ◽  
Important Conclusion ◽  
Miller Index ◽  
Orbital Population ◽  
Metal Metal ◽  
Metal Bonds

The ion-driven mechanism in hydrogen permeation is substantially modified when iron is coated with palladium. A detailed knowledge of the electronic structure at the metal–metal interfaces is a prerequisite for understanding the process of H permeation. We have selected two low-Miller-index surfaces as a simple model for the interface. The system under consideration has 148 metallic atoms forming an Fe–Pd cluster distributed in six metallic layers. We have investigated the interaction of atomic hydrogen with the Fe (110)– Pd (100) interface using the semiempirical atom superposition and electron delocalization (ASED-MO) method. The changes in the electronic structures, density of states (DOS) and crystal overlap orbital population (COOP) in two different Fe–Pd interfaces were compared with the bulk ground states of both metals. The interfacial Fe–Pd distance results in about 1.74 Å, whereas for the Fe–Pd first neighbors distance it is about 1.85 Å. An important conclusion is that the metal–metal bonds at the interface are stronger than those bonds in the pure metal bulk. A favorable metal adhesion is observed, as revealed by the energetic stabilization of the composite metal system. H is stabilized near the FePd interface and stopped at the first Pd layer. A H–metal bond is developed with both Fe and Pd atoms while Fe–Pd bonding at the interface remains unaltered.

First-principles investigation on environmental embrittlement of TiAl

1998 ◽  
Vol 13 (2) ◽  
pp. 290-301 ◽  
Author(s):  
Y. Liu ◽  
K. Y. ◽  
J. H. Zhang ◽  
G. Lu ◽  
Z. Q. Hu
Keyword(s):  
Hydrogen Embrittlement ◽  
First Principles ◽  
Electronic Structures ◽  
Bond Order ◽  
Environmental Embrittlement ◽  
Cohesive Properties ◽  
Metal Metal ◽  
Metal Metal Bonds ◽  
Metal Bonds ◽  
Mn Doped

To investigate the hydrogen embrittlement and Mn ductilization effects in TiAl, the electronic structures of pure, H-doped, Mn-doped, and Mn, H-codoped TiAl have been studied by the first-principles discrete variational Xa calculations. Local environmental total bond order (LTBO), which is developed for the description of the cohesive properties in a local atom environment involving impurities, should be regarded as a new microscopic criterion for embrittlement. The larger LTBO presents the stronger cohesion and the better ductility of the system. Our results show that H obviously decreases LTBO while Mn increases it, which suggests H as an embrittler while Mn as a ductilizer. It is of key importance to understand hydrogen embrittlement in which hydrogen causes the weakening of its surrounding metal-metal bonds.

One-dimensional complexes extended by unbridged metal–metal bonds based on a HOMO–LUMO interaction at the dz2orbital between platinum and heterometal atoms

2017 ◽  
Vol 46 (17) ◽  
pp. 5474-5492 ◽  
Author(s):  
Kazuhiro Uemura
Keyword(s):  
Electronic Structures ◽  
Dimensional Chain ◽  
One Dimensional ◽  
Chain Complexes ◽  
Metal Metal ◽  
Metal Metal Bonds ◽  
Metal Bonds ◽  
Homo Lumo

Crystal and electronic structures of seventeen heterometallic one-dimensional chain complexes are reviewed and discussed.

Effect of Helium on the Electronic Structure of Palladium Tritide

1998 ◽  
Vol 513 ◽  
Author(s):  
R. P. Gupta ◽  
M. Gupta
Keyword(s):  
Electronic Structure ◽  
Ab Initio ◽  
Electronic Structure Calculations ◽  
Plateau Pressure ◽  
Recoil Energy ◽  
Repulsive Interaction ◽  
Metal Metal ◽  
Metal Bonds ◽  
Structure Calculations ◽  
Ab Initio Electronic Structure

ABSTRACTTritium is usually stored in the form of a metal tritide since it is safe to handle in this form, easily recoverable, and further large quantities of tritium can be stored. However, since tritium is radioactive it decays into 3He and an electron. Helium recoil energy in this reaction is very small, and not enough to create defects. We have performed ab-initio electronic structure calculations that show that in PdT, a considerable amount of 3He can be accommodated at the 3He results in an overall enhancement in the strength of the metal- tritium bonding that leads to the lowering of the plateau pressure. We also find that there is a weakening of the metal-metal bonds due to the repulsive interaction with 3He.

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