Formation of surface layer of hydrogen in pure aluminum

2019 ◽  
Vol 484 (1) ◽  
pp. 56-60
Author(s):  
D. A. Indejtsev ◽  
E. V. Osipova
Keyword(s):  
Surface Layer ◽  
Hydrogen Atom ◽  
Ab Initio ◽  
Pure Aluminum ◽  
Hydrogen Atoms ◽  
Energy Characteristics ◽  
Aluminum Crystal

Hydrogen atom behavior in pure aluminum is described by ab initio modelling. All main energy characteristics of the system consisting of hydrogen atoms in a periodic aluminum crystal are found.

Interaction of Hydrogen Atom with Edge Dislocation in Pd and Ni

2018 ◽  
Vol 30 ◽  
pp. 46-51
Author(s):  
Irina V. Zorya ◽  
Gennady M. Poletaev ◽  
Mikhail D. Starostenkov
Keyword(s):  
Molecular Dynamics ◽  
Hydrogen Atom ◽  
Sorption Capacity ◽  
Edge Dislocation ◽  
Dislocation Core ◽  
Hydrogen Impurity ◽  
Hydrogen Atoms ◽  
Energy Characteristics ◽  
Method Of Molecular Dynamics ◽  
Diffusion Of Hydrogen

The energy characteristics of interaction of hydrogen impurity with ½<110> edge dislocation in Pd and Ni were calculated by the method of molecular dynamics. It is shown that the dislocation is effective trap for hydrogen. At the same time the dislocation jogs increases its sorption capacity with respect to hydrogen, but reduces the diffusion mobility of hydrogen along the dislocation. The diffusion of hydrogen atoms in the dislocation region occurs mainly along the dislocation core. The energy of hydrogen migration along the dislocation, as our calculations have shown, is almost two times lower than in a defect-free crystal.

Hydrogen adsorbed in ab initio computationally simulated nanoporous carbon. An energetics study

2007 ◽  
Vol 1042 ◽  
Author(s):  
R. M. Valladares ◽  
Alexander Valladares ◽  
A. G. Calles ◽  
Ariel A. Valladares
Keyword(s):  
Hydrogen Atom ◽  
Binding Energy ◽  
Total Energy ◽  
Ab Initio ◽  
Molecular Hydrogen ◽  
Molecular Form ◽  
Average Energy ◽  
Nanoporous Carbon ◽  
Hydrogen Atoms ◽  
Pure Carbon

AbstractNanoporous carbon has been considered an interesting and potentially useful material for storing hydrogen. Using nanoporous carbon periodic supercells with 216 atoms and 50 % porosity, constructed with a novel ab initio approach devised by us, the dangling bonds of the carbon atoms were first saturated with hydrogen, then relaxed and its total energy calculated with and without hydrogen. Next the same number of hydrogen atoms, in molecular form, was randomly placed within the pore of the pure carbon supercell, then the sample relaxed, and finally its total energy calculated, also with and without hydrogens. From these results the average energy per hydrogen atom is obtained for both cases. For the molecular hydrogen sample the binding energy found per hydrogen atom is 343.89 meV, which compares favourably with values reported in the literature, 300-400 meV/molecule.

Ab Initio Determination of a New Complex Structure (55 Non-Hydrogen Atoms) from Synchrotron Powder Data: An Uncommon Nickel Succinate, Ni7(C4H4O4)4(OH)6(H2O)3•7H2O

2004 ◽  
Vol 443-444 ◽  
pp. 333-336
Author(s):  
N. Guillou ◽  
C. Livage ◽  
W. van Beek ◽  
G. Férey
Keyword(s):  
Ab Initio ◽  
Complex Structure ◽  
Three Dimensional ◽  
Free Water ◽  
Hydrogen Atoms ◽  
Monoclinic System ◽  
Synchrotron Powder Diffraction ◽  
Chloride Hexahydrate ◽  
Autogenous Pressure

Ni7(C4H4O4)4(OH)6(H2O)3. 7H2O, a new layered nickel(II) succinate, was prepared hydrothermally (180°C, 48 h, autogenous pressure) from a 1:1.5:4.1:120 mixture of nickel (II) chloride hexahydrate, succinic acid, potassium hydroxide and water. It crystallizes in the monoclinic system (space group P21/c, Z = 4) with the following parameters a = 7.8597(1) Å, b = 18.8154(3)Å, c = 23.4377(4) Å,ϐ = 92.0288(9)°, and V = 3463.9(2) Å3. Its structure, which contains 55 non-hydrogen atoms, was solved ab initio from synchrotron powder diffraction data. It can be described from hybrid organic-inorganic layers, constructed from nickel oxide corrugated chains. These chains are built up from NiO6hexameric units connected via a seventh octahedron. Half of the succinates decorate the chains, and the others connect them to form the layers. The three dimensional arrangement is ensured by hydrogen bonds directly between two adjacent layers and via free water molecules.

Hydrogenated Amorphous Silicon Nitride: Structural and Electronic Properties

1998 ◽  
Vol 538 ◽  
Author(s):  
J. F. Justo ◽  
F. De Brito Mota ◽  
A. Fazziom
Keyword(s):  
Silicon Nitride ◽  
Ab Initio ◽  
Amorphous Silicon ◽  
Electronic Properties ◽  
Interatomic Potential ◽  
Hydrogen Atoms ◽  
Hydrogen Incorporation ◽  
Amorphous Silicon Nitride ◽  
Structural And Electronic Properties ◽  
Hydrogenated Amorphous

AbstractWe combined empirical and ab initio methods to study structural and electronic properties of amorphous silicon nitride. For such study, we developed an interatomic potential to describe the interactions between silicon, nitrogen, and hydrogen atoms. Using this potential, we performed Monte Carlo simulations in a simulated annealing scheme to study structural properties of amorphous silicon nitride. Then this potential was used to generate relevant structures of a-SiNx:Hy which were input configurations to ab initio calculations. We investigated the electronic and structural role played by hydrogen incorporation in amorphous silicon nitride.

scholarly journals Toward fully quantum modelling of ultrafast photodissociation imaging experiments. Treating tunnelling in the ab initio multiple cloning approach

2016 ◽  
Vol 194 ◽  
pp. 81-94 ◽  
Author(s):  
Dmitry V. Makhov ◽  
Todd J. Martinez ◽  
Dmitrii V. Shalashilin
Keyword(s):  
Kinetic Energy ◽  
Ab Initio ◽  
Energy Release ◽  
Kinetic Energy Release ◽  
Total Kinetic Energy ◽  
Recent Effort ◽  
Experimental Measurements ◽  
Quantum Level ◽  
Hydrogen Atoms ◽  
Quantum Simulations

We present an account of our recent effort to improve simulation of the photodissociation of small heteroaromatic molecules using the Ab Initio Multiple Cloning (AIMC) algorithm. The ultimate goal is to create a quantitative and converged technique for fully quantum simulations which treats both electrons and nuclei on a fully quantum level. We calculate and analyse the total kinetic energy release (TKER) spectra and Velocity Map Images (VMI), and compare the results directly with experimental measurements. In this work, we perform new extensive calculations using an improved AIMC algorithm that now takes into account the tunnelling of hydrogen atoms. This can play an extremely important role in photodissociation dynamics.

scholarly journals The photolysis of ammonia

1940 ◽  
Vol 175 (961) ◽  
pp. 187-207 ◽  
Keyword(s):  
Hydrogen Atom ◽  
Preceding Paper ◽  
Ammonia Molecule ◽  
Experimental Techniques ◽  
Hydrogen Atoms ◽  
Atom Concentration ◽  
Important Discrepancy

It has been shown in the preceding paper that the hypothesis that hydrazine is responsible for the anomalously low hydrogen atom concentration in the decomposition of ammonia must be abandoned. In order to explain this important discrepancy some new experimental techniques require to be developed which will settle the matter without appeal to further hypotheses. There are two general explanations of the discrepancy: (1) the hydrogen atoms are not produced as fast as that calculated on the assumption that every ammonia molecule absorbing a quantum necessarily decomposes, (2) that some entity not yet recognized removes hydrogen atoms at a rate faster than that at which they normally recombine. In this paper methods will be described in which these two problems are solved, and finally there is a discussion of the photochemistry of ammonia in the light of the new results obtained during these experiments.

scholarly journals Relationship between the Behavior of Hydrogen and Hydrogen Bubble Nucleation in Vanadium

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 322
Author(s):  
Zhengxiong Su ◽  
Sheng Wang ◽  
Chenyang Lu ◽  
Qing Peng
Keyword(s):  
Hydrogen Atom ◽  
First Principles ◽  
Bound States ◽  
Hydrogen Molecule ◽  
Vacancy Cluster ◽  
Bubble Nucleation ◽  
Hydrogen Bubble ◽  
First Principles Calculations ◽  
Hydrogen Atoms ◽  
Macroscopic Deformation

Hydrogen plays a significant role in the microstructure evolution and macroscopic deformation of materials, causing swelling and surface blistering to reduce service life. In the present work, the atomistic mechanisms of hydrogen bubble nucleation in vanadium were studied by first-principles calculations. The interstitial hydrogen atoms cannot form significant bound states with other hydrogen atoms in bulk vanadium, which explains the absence of hydrogen self-clustering from the experiments. To find the possible origin of hydrogen bubble in vanadium, we explored the minimum sizes of a vacancy cluster in vanadium for the formation of hydrogen molecule. We show that a freestanding hydrogen molecule can form and remain relatively stable in the center of a 54-hydrogen atom saturated 27-vacancy cluster.

The structure and energetics of low-lying states of RCO and RNN free radicals

1977 ◽  
Vol 55 (5) ◽  
pp. 863-868 ◽  
Author(s):  
N. Colin Baird ◽  
Harish B. Kathpal
Keyword(s):  
Experimental Data ◽  
Free Radicals ◽  
Hydrogen Atom ◽  
Ab Initio ◽  
Open Shell ◽  
Basis Set ◽  
Basis Sets ◽  
Mo Calculations ◽  
Decomposition Products ◽  
Ab Initio Mo Calculations

The important geometrical variables in the structures of the lowest 2A′ and 2A′′ states of the free radicals HCO, CH3CO, NH2CO, HNN, and CH3NN have been determined by ab initio MO calculations using the STO-3G basis set. The energy differences between the states, and the energies of the radicals relative to their decomposition products and relative to their hydrogen atom addition products, are reported using both STO-3G and 4-31G basis sets in the restricted open-shell calculations. The trends in these results and their relation to available experimental data are discussed.

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