Ab initio techniques for ground state calculations on polymers

2008 ◽  
pp. 56-79 ◽  
Author(s):  
M. Kertesz ◽  
J. Koller ◽  
A. Azman
Keyword(s):  
Ab Initio ◽  
Ground State

scholarly journals THE METHOD OF INCREMENTS — A WAVEFUNCTION-BASED AB-INITIO CORRELATION METHOD FOR SOLIDS

2007 ◽  
Vol 21 (13n14) ◽  
pp. 2204-2214 ◽  
Author(s):  
BEATE PAULUS
Keyword(s):  
Experimental Data ◽  
Ab Initio ◽  
Ground State ◽  
Infinite System ◽  
Correlation Energy ◽  
Correlation Method ◽  
Many Body ◽  
Hartree Fock ◽  
The Many ◽  
Good Agreement

The method of increments is a wavefunction-based ab initio correlation method for solids, which explicitly calculates the many-body wavefunction of the system. After a Hartree-Fock treatment of the infinite system the correlation energy of the solid is expanded in terms of localised orbitals or of a group of localised orbitals. The method of increments has been applied to a great variety of materials with a band gap, but in this paper the extension to metals is described. The application to solid mercury is presented, where we achieve very good agreement of the calculated ground-state properties with the experimental data.

VUV FRAGMENTATION OF SOME HYDROFLUOROCARBON CATIONS STUDIED USING COINCIDENCE TECHNIQUES

2002 ◽  
Vol 09 (01) ◽  
pp. 153-158 ◽  
Author(s):  
WEIDONG ZHOU ◽  
D. P. SECCOMBE ◽  
R. Y. L. CHIM ◽  
R. P. TUCKETT
Keyword(s):  
Kinetic Energy ◽  
Ab Initio ◽  
Ground State ◽  
Lower Energy ◽  
Lone Pair ◽  
Electronic States ◽  
Photoelectron Spectra ◽  
Highest Occupied Molecular Orbital ◽  
Impulsive Model ◽  
Lone Pair Electrons

Threshold photoelectron–photoion coincidence (TPEPICO) spectroscopy has been used to investigate the decay dynamics of the valence electronic states of the parent cation of several hydrofluorocarbons (HFC), based on fluorine-substituted ethane, in the energy range 11–25 eV. We present data for CF 3– CHF 2, CF 3– CH 2 F , CF 3– CH 3 and CHF 2– CH 3. The threshold photoelectron spectra (TPES) of these molecules show a common feature of a broad, relatively weak ground state, associated with electron removal from the highest-occupied molecular orbital (HOMO) having mainly C–C σ-bonding character. Adiabatic and vertical ionisation energies for the HOMO of the four HFCs are presented, together with corresponding values from ab initio calculations. For those lower-energy molecular orbitals associated with non-bonding fluorine 2pπ lone pair electrons, these electronic states of the HFC cation decay impulsively by C–F bond fission with considerable release of translational kinetic energy. Appearance energies are presented for formation of the daughter cation formed by such a process (e.g. CF 3– CHF +), together with ab initio energies of the corresponding dissociation channel (e.g. CF 3– CHF + + F ). Values for the translational kinetic energy released are compared with the predictions of a pure-impulsive model.

Ab-Initio Calculations of the Electronic Structure and Properties of Titanium Carbosulfide

1995 ◽  
Vol 408 ◽  
Author(s):  
Bala Ramalingam ◽  
Michael E. McHenry ◽  
Warren M. Garrison ◽  
James M. MacLaren
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Ground State ◽  
Manganese Sulfide ◽  
Structure And Properties ◽  
Host Matrix ◽  
Inclusion Phase ◽  
Equilibrium Lattice Constant ◽  
Volume Curve ◽  
Titanium Carbosulfide

AbstractTitanium carbosulfide (Ti2CS) is frequently found as an inclusion phase in Ti - containing steels. It is of considerable interest because, whenever present in preference to the more common manganese sulfide (MnS), it significantly improves the toughness (a very desirable property) of the steel. Currently, to the best of our knowledge, there is no data, either computational or experimental, regarding the structural properties of Ti2CS. This data is needed to understand the influence of the Ti2CS inclusions on the toughness of the host material.In this paper, our results from the ab-initio calculations, using the LKKR-ASA (Layer Korringa Kohn Rostoker method in the Atomic Spheres Approximation) on the equilibrium ground state properties of bulk Ti2CS are presented and discussed. In particular, attention is focused upon (a) the Energy – Atomic Volume curve generated to calculate the equilibrium lattice constant and the bulk modulus, and (b) the density of states calculations. The application of these results to the subsequent study of an interface involving the carbosulfide and the host matrix is also illustrated.

Accurate Potential Energy Curve for B2. Ab Initio Elucidation of the Experimentally Elusive Ground State Rotation-Vibration Spectrum

2012 ◽  
Vol 116 (7) ◽  
pp. 1717-1729 ◽  
Author(s):  
Laimutis Bytautas ◽  
Nikita Matsunaga ◽  
Gustavo E. Scuseria ◽  
Klaus Ruedenberg
Keyword(s):  
Potential Energy ◽  
Ab Initio ◽  
Ground State ◽  
Potential Energy Curve ◽  
Vibration Spectrum ◽  
Energy Curve

scholarly journals A new ab initio ground-state dipole moment surface for the water molecule

2008 ◽  
Vol 128 (4) ◽  
pp. 044304 ◽  
Author(s):  
Lorenzo Lodi ◽  
Roman N. Tolchenov ◽  
Jonathan Tennyson ◽  
A. E. Lynas-Gray ◽  
Sergei V. Shirin ◽  
...  
Keyword(s):  
Dipole Moment ◽  
Water Molecule ◽  
Ab Initio ◽  
Ground State ◽  
Ground State Dipole Moment

scholarly journals Ground-state properties of Na2IrO3 determined from an ab initio Hamiltonian and its extensions containing Kitaev and extended Heisenberg interactions

2017 ◽  
Vol 96 (5) ◽  
Author(s):  
Tsuyoshi Okubo ◽  
Kazuya Shinjo ◽  
Youhei Yamaji ◽  
Naoki Kawashima ◽  
Shigetoshi Sota ◽  
...  
Keyword(s):  
Ab Initio ◽  
Ground State ◽  
Ground State Properties
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