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Rigorous results in electronic structure calculations
Rigorous results in electronic structure calculations

... the normalized wave function of a system of identical particles is either symmetric, when z = 1, or antisymmetric, when z = −1, with respect to the interchange of any two identical particles. Particles with symmetric wave functions are called bosons, and particles with antisymmetric wave functions a ...
1 Equations of Steady Electric and Magnetic Fields in - Wiley-VCH
1 Equations of Steady Electric and Magnetic Fields in - Wiley-VCH

Dipole-bound anions of highly polar molecules: Ethylene carbonate
Dipole-bound anions of highly polar molecules: Ethylene carbonate

... * is the effective principal quantum number of the where n max Rydberg atom that produces the greatest yield of dipolebound anions. This method has been recently applied to a large number 共27兲 of molecules possessing dipole moments between 2.5 and 4.3 D.11 The applicability of this relationship to h ...
Theoretical Modeling of Transport in Nanostructures June 02, 2009
Theoretical Modeling of Transport in Nanostructures June 02, 2009

... spin excitations that can be probed in simple tunneling-spectroscopy transport [1, 2]. We explore the possibility of using QMC techniques to calculate the conductance through a Kondo correlated quantum dot. (2) Interaction-induced localization in an inhomogeneous quantum wire-- We study the localiza ...
Enhancement of Tunneling from a Correlated 2D Electron System
Enhancement of Tunneling from a Correlated 2D Electron System

... correlation effects are small. We expect that tunneling experiments on low-density 2DESs in parallel fields will reveal electron correlations not imposed by the magnetic field, give insight into electron dynamics, and possibly even reveal a transition from an electron fluid to a pinned Wigner crysta ...
Interference of Bose#Einstein Condensates†
Interference of Bose#Einstein Condensates†

Basic Conceptions: Spin Exchange and Electron Transfer
Basic Conceptions: Spin Exchange and Electron Transfer

Dual Density Operators and Natural Language
Dual Density Operators and Natural Language

... entailment? We resolve this dilemma by introducing dual density operators. These are mathematical entities which admit ‘two independent dimensions’ of being a density operator. Moreover, just like ordinary density operators, these dual density operators inhabit a category of the appropriate structur ...
INTERPLAY BETWEEN STRUCTURAL AND ELECTRONIC PROPERTIES OF CARBON NANOTUBES
INTERPLAY BETWEEN STRUCTURAL AND ELECTRONIC PROPERTIES OF CARBON NANOTUBES

Breaking Multiple Covalent Bonds with Hartree-Fock-based
Breaking Multiple Covalent Bonds with Hartree-Fock-based

Ab initio theory of ferromagnetic transition metals and alloys under
Ab initio theory of ferromagnetic transition metals and alloys under

... of the present theory is the set of interatomic exchange parameters Jij . These parameters will be extracted from realistic band structure calculation for a particular system and their pressure dependence will be studied. Their change with lattice contraction is not straightforward to predict. On on ...
Born approximation - BYU Physics and Astronomy
Born approximation - BYU Physics and Astronomy

... What is the main idea of the Born approximation? A. To develop a formalism where we express the wave function in terms of Green’s functions B. To use Helmholtz equation instead of Schrödinger equation C. To find an approximate expression for  when far away from the scattering center for a given pot ...
An Introduction to Theoretical Chemistry - Beck-Shop
An Introduction to Theoretical Chemistry - Beck-Shop

... Theoretical treatment of electronic structure: atomic and molecular orbital theory In Chapter 5’s discussion of molecular structure, I introduced you to the strategies that theory uses to interpret experimental data relating to such matters, and how and why theory can also be used to simulate the be ...
First Principles Investigation into the Atom in Jellium Model System
First Principles Investigation into the Atom in Jellium Model System

... List of Figures ...
EE 5340©
EE 5340©

... Newtonian Mechanics • Kinetic energy, KE = mv2/2 = p2/2m Conservation of Energy Theorem • Momentum, p = mv Conservation of Momentum Thm • Newton’s second Law F = ma = m dv/dt = m d2x/dt2 ...
Theoretical Chemistry I Quantum Mechanics
Theoretical Chemistry I Quantum Mechanics

Time-dependent density equation and perturbation th
Time-dependent density equation and perturbation th

... approximations which were valid essentially up to second-order in electron correlations. As clearly understood from the argument based on Fig. 1, these decoupling formulas constitute the (approximate) N -representability conditions. In this formalism, Valdemoro's approximation is shown to be valid u ...
Local structure relaxation, quantum trap depression, and
Local structure relaxation, quantum trap depression, and

Probability Current and Current Operators in Quantum Mechanics 1
Probability Current and Current Operators in Quantum Mechanics 1

... From the continuity equation, this can be connected to the current we are looking for, by ~ ·j=e ...
Spontaneous Formation of Magnetic Moments and Dephasing in Two-Dimensional Disordered Systems
Spontaneous Formation of Magnetic Moments and Dephasing in Two-Dimensional Disordered Systems

... dots [6] by the addition of constant e2 /h, which sets the high temperature limit to e2 /h, and by the fixing of the prefactor of f (T /Tk ) to 1/2. Another feature of the Kondo regime (T < Tk ) in quantum dots is that the zero bias peak is split by 2g ∗ µB B with an in-plane magnetic field when g ...
Analytical approach to the helium
Analytical approach to the helium

... on the one hand, screen the nuclear charge and, on the other hand, produce a change in the centrifugal potential term that appears in the radial part of the one-electron Schrödinger equation. The interelectronic interaction is repulsive. Therefore, mechanistically, one may think of this repulsion r ...
1 Bonding in Molecular Crystals from the Local Electronic Pressure
1 Bonding in Molecular Crystals from the Local Electronic Pressure

Short-pulse space-charge-limited electron flows
Short-pulse space-charge-limited electron flows

... same over-injection method27 in a planar drift space with a gap separation much smaller than the electrode size 共1D model兲. A finite pulse ␶ p of current density J is injected into the gap, and the value of J is increased until the formation of a virtual cathode, which will cause the reflection of e ...
Electron spectroscopy of atoms and molecules using synchrotron
Electron spectroscopy of atoms and molecules using synchrotron

... (i.e. one electron atom or ions of general atomic number Z). The SE form for many-electron atoms is too complicated to be solved exactly and a number of approximations are necessary on the path to finding a solution. In first approximation, H3 can be separated into two parts, one of which is spherical ...
I. Parity violation induced by weak neutral currents in atomic
I. Parity violation induced by weak neutral currents in atomic

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Density functional theory

Density functional theory (DFT) is a computational quantum mechanical modelling method used in physics, chemistry and materials science to investigate the electronic structure (principally the ground state) of many-body systems, in particular atoms, molecules, and the condensed phases. Using this theory, the properties of a many-electron system can be determined by using functionals, i.e. functions of another function, which in this case is the spatially dependent electron density. Hence the name density functional theory comes from the use of functionals of the electron density. DFT is among the most popular and versatile methods available in condensed-matter physics, computational physics, and computational chemistry.DFT has been very popular for calculations in solid-state physics since the 1970s. However, DFT was not considered accurate enough for calculations in quantum chemistry until the 1990s, when the approximations used in the theory were greatly refined to better model the exchange and correlation interactions. In many cases the results of DFT calculations for solid-state systems agree quite satisfactorily with experimental data. Computational costs are relatively low when compared to traditional methods, such as Hartree–Fock theory and its descendants based on the complex many-electron wavefunction.Despite recent improvements, there are still difficulties in using density functional theory to properly describe intermolecular interactions (of critical importance to understanding chemical reactions), especially van der Waals forces (dispersion); charge transfer excitations; transition states, global potential energy surfaces, dopant interactions and some other strongly correlated systems; and in calculations of the band gap and ferromagnetism in semiconductors. Its incomplete treatment of dispersion can adversely affect the accuracy of DFT (at least when used alone and uncorrected) in the treatment of systems which are dominated by dispersion (e.g. interacting noble gas atoms) or where dispersion competes significantly with other effects (e.g. in biomolecules). The development of new DFT methods designed to overcome this problem, by alterations to the functional and inclusion of additional terms to account for both core and valence electrons or by the inclusion of additive terms, is a current research topic.
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