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Littérature scientifique sur le sujet « Electronic Correlation Theories »

Auteur : Grafiati
Publié le 7 septembre 2023

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Articles de revues sur le sujet "Electronic Correlation Theories"

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Ke-He, Su, Wei Jun, Hu Xiao-Ling, Yue Hong, Lv Ling, Wang Yu-Bin et Wen Zhen-Yi. « Core Electronic Correlation Modifications to G2 and G2(QCL) Theories ». Acta Physico-Chimica Sinica 16, no 11 (2000) : 972–80. http://dx.doi.org/10.3866/pku.whxb20001104.

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YU, ZHI-MING, QING-WEI WANG et YU-LIANG LIU. « THE ELECTRONIC CORRELATION EFFECT FROM WEAK TO STRONG IN THE THREE DIMENSIONAL ELECTRON GAS ». International Journal of Modern Physics B 26, no 11 (30 avril 2012) : 1250065. http://dx.doi.org/10.1142/s0217979212500658.

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Based on the success of the eigenfunctional theory ( EFT) in the one-dimensional model,16,24,51 we apply it to the three-dimensional homogeneous electron gas. By EFT, we first present a rigorous expression of the pair distribution function g(r) of the electron gas. This expression effectively solves the negative problem of g(r) that when electronic correlation effect is strong, the previous theories give a negative g(r),9 while g(r) is strictly a positive function. From this reasonable g(r), we estimate and establish a newly effective fitting expression of the ground state energy of electron gas. The new fitting expression presents a similar result with present theories when rs is small, since only in the limit of rs is small, present theories estimate a exact ground state energy. When rs increases, the difference between EFT and other theories becomes more and more remarkable. The difference is expected as EFT estimates a reasonable g(r) and would effectively amend the overestimate of previous theories in the ground state energy. In addition, by the ground state energy, we estimate the phase transition derived by the strong correlation effect. When the density decreases, the electronic correlation effect changes from weak to strong and we observe a sudden phase transition from paramagnetic to full spin polarization occurring at rs = 31 ± 4.
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Benavides-Riveros, Carlos L., Nektarios N. Lathiotakis et Miguel A. L. Marques. « Towards a formal definition of static and dynamic electronic correlations ». Physical Chemistry Chemical Physics 19, no 20 (2017) : 12655–64. http://dx.doi.org/10.1039/c7cp01137g.

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Some of the most spectacular failures of density-functional and Hartree–Fock theories are related to an incorrect description of the so-called static electron correlation. Motivated by recent progress in the N-representability problem of the one-body density matrix for pure states, we propose a way to quantify the static contribution to the electronic correlation.
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Liu, Yu, Terry J. Frankcombe et Timothy W. Schmidt. « Electronic Wavefunction Tiles ». Australian Journal of Chemistry 73, no 8 (2020) : 757. http://dx.doi.org/10.1071/ch19517.

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We review the pre-quantum theories of electronic structure of Lewis and Langmuir, and how this relates to the post-quantum double-quartet theory of Linnett. Linnett’s ideas are put on a firm theoretical footing through the emergence of the wavefunction tile: The 3N-dimensional repeating structure of the N-electron wavefunction. Wavefunction tiles calculated by the dynamic Voronoi Metropolis sampling method are reviewed, and new results are presented for bent bonds of cyclopropane, and electron correlation in Be-O-Be.
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Podeszwa, Rafał. « Electronic correlation in cyclic polyenes. Behavior of approximate coupled-pair theories for large rings ». Chemical Physics Letters 365, no 3-4 (octobre 2002) : 211–15. http://dx.doi.org/10.1016/s0009-2614(02)01451-3.

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Zhang, Tianshi, Ziming Mo, Xiaoyu Xu, Xiaoyan Liu, Haopeng Chen, Zhiwu Han, Yuying Yan et Yingai Jin. « Advanced Study of Spray Cooling : From Theories to Applications ». Energies 15, no 23 (5 décembre 2022) : 9219. http://dx.doi.org/10.3390/en15239219.

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With the continuous integration and miniaturization of electronic devices, the heat transfer of the electronic devices continues to surge. This means that thermal management equipment with higher heat flux cooling capacity is required to maintain its normal operation. This paper systematically reviews the progress of spray cooling. In the first part, the thermal dissipation mechanism of spray cooling in the non-boiling regime and boiling regime are summarized, and the correlation formula of heat transfer is summarized. In the second part, the influencing factors of various parameters of the nozzle are summarized, the experimental research and numerical simulation research are summarized separately, and some means and methods to strengthen heat transfer are listed. In the third part, we summarize the current application research of spray cooling in some hot new fields, including electronic technology, aerospace, biomedicine, battery safety, etc. The research prospects and challenges in these fields are highlighted. This research provides a timely and necessary study of spray cooling.
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March, N. H. « Liquid Structural Theories Related via a Force Correlation Function ». Physics and Chemistry of Liquids 16, no 3 (février 1987) : 205–8. http://dx.doi.org/10.1080/00319108708078519.

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Xing, Yu-Mei, Lan Chen, Chong Zhang, Zun-Sheng Cai et Xue-Zhuang Zhao. « Semiclassical and quantum-mechanical study of the reaction mechanism for the N2 + N2+ electron transfer system ». Canadian Journal of Chemistry 81, no 2 (1 février 2003) : 125–32. http://dx.doi.org/10.1139/v03-005.

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Density functional theory (DFT) calculations, including electron correlation, were carried out on the N2 + N2+ electron transfer system. Six geometries of the precursor complex were assumed and their stabilities were calculated and compared. The activation energy, the electronic transmission factor, and the electronic coupling matrix element in the electron transfer process were also calculated. The electronic transmission factor for this system was far less than unity (ca. 0.006~0.09); thus, the electron transfer reaction was considered to be diabatic in nature. Therefore, the electron transfer rate for the selected structures was calculated using semiclassical and quantum-mechanical theories. The calculated values were compared with each other and were in good agreement with the experimental value.Key words: N2 + N2+ electron transfer reaction, semiclassical and quantum-mechanical theories, electronic transmission factor, electronic coupling matrix element, B3LYP.
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McCarthy, IE. « Electronic Structure of Atoms, Molecules and Solids from (e,2e) Studies ». Australian Journal of Physics 43, no 5 (1990) : 419. http://dx.doi.org/10.1071/ph900419.

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The (e,2e) reaction on atoms can be described quite well in most of kinematic space by distorted-wave theories of varying sophistication. In some regions it is necessary to obey the newly-discovered boundary condition for three charged particles. The understanding enables us to recognise a kinematic region where the reaction is sensitive only to the target-ion structure. Single-particle and electron-correlation information has been discovered for a wide range of atoms and molecules. The understanding of solids is developing.
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Garza, Alejandro J., Carlos A. Jiménez-Hoyos et Gustavo E. Scuseria. « Electronic correlation without double counting via a combination of spin projected Hartree-Fock and density functional theories ». Journal of Chemical Physics 140, no 24 (28 juin 2014) : 244102. http://dx.doi.org/10.1063/1.4883491.

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Thèses sur le sujet "Electronic Correlation Theories"

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Sharma, Anand. « Electronic correlation and magnetism in multi-band Kondo lattice models ». Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2009. http://dx.doi.org/10.18452/15968.

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Die vorliegende Arbeit untersucht elektronische Korrelationseffekte in Realsubstanzen wie Europium-Sulphid (EuS) und Gadolinium-Nitrid (GdN). Es wird dazu eine Kombination von vielteilchentheoretischen Analysen der Spin-Austauschwechselwirkung zwischen itineranten Bandelektronen und lokalisierten 4f-Momenten, durchgefuehrt im Rahmen eines Mehr-Band-Kondo-Gitter-Modells (KLM), mit first-principles (T=0) Bandstrukturrechnungen vorgeschlagen. Die Ein-Teilchen-Energien (hopping-Integrale), die als Energie-Matrix in den Mehr-Band-Hamilton-Operator eingehen, werden einer TB-LMTO-ASA entnommen. Die interessierenden physikalischen Eigenschaften wie die Quasiteilchen-Spektraldichte und die Quasiteilchen-Zustandsdichte werden mit der Bewegu-ngsgleichungs-Methode Greencher Funktionen berechnet. Dazu wird fuer die gesuchte Mehr-Band-Selbstenergie der itinerantenLadungstraeger als Verallgemeinerung des sogenannten Interpolating Selfenergy Approach (ISA) ein Ansatz vorgeschlagen. Es stellt sich heraus, dassdas elektronische Anregungsspektrum durch die Austausch-Kopplung an das lokalisierte Momenten-System eine spektakulaere Temperaturabhaengigkeit aufweist, in Uebereinstimmung mit vorliegenden experimentellen Beobachtungen. Stark temperaturbestimmte Korrelationseffekte werden registriert, z.B. eine mit fallender Temperatur in der ferromagnetischen Phase auftretende Rotverschiebung der unteren Leitungsbandkante in guter Uebereinstimmung mit experimentellen Daten. Um die reinen f-Spin-Korrelationen zu beschreiben, wird eine modifizierte RKKY-Theorie fuer Mehr-Band-Systeme entwickelt, wobei durch Ausmitteln der elektronischen Freiheitsgrade das Mehr-Band KLM auf ein effektives Heisenberg-Modell abgebildet wird. Mit einer RPA-Theorie wird das effektive Heisenberg-Modell auf Aussagen zu zentralen magnetischen Eigenschaften wie Curie-Temperatur und Magnetisierungskurve analysiert. Durch gezielte Variation der Systemparameter wird die Brauchbarkeit des Modells getestet.
This dissertation deals with a combination of many-body evaluation of a spin exchange interaction between the itinerant electrons and localized 4f moments on a periodic lattice, i.e. within the so-called multi-band Kondo lattice model (KLM), and the T=0 first principles calculations in order to study the electronic correlation effects in real materials like Europium Sulphide (EuS) and Gadolinium Nitride (GdN).The single-particle ground state energy or hopping integral acting as an input in the many-body part is obtained using tight binding linear muffin-tin orbital within atomic sphere approximation (TB-LMTO-ASA) program and is a matrix in general. The physical properties of interest like the quasi-particle spectral density and quasi-particle density of states are calculated within the Green function theory and the equation of motion method. In order to do so the required multi-band self-energy of the band electrons istaken as an ansatz, i.e. the so-called interpolating self-energy approach (ISA). The electronic excitation spectrum gets a striking temperature dependence by its exchange coupling to the localized spin system. We observe very strong temperature dependent electronic correlation effects in GdN and the calculated red-shift of the lower conduction band is in close comparison with experiment. In order to determine the pure f-spin correlations, we develop the multi-band modified RKKY theory. The central idea of this theory beingto average out the itinerant electron degrees of freedom from the spin-exchange interaction and map the latter on to an effective Heisenberg model. Using this procedure, we determine the magnetic properties of the system like Curie temperature (within Random Phase Approximation) while calculating the chemical potential and magnetization within a self consistent scheme for various configurations of system parameters.
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Phiri, Temwani-Joshua. « Correlation between SQUID and fluxgate magnetometer data for geomagnetic storms ». Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/80364.

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Thesis (MScEng)--Stellenbosch University, 2013.
ENGLISH ABSTRACT: Geomagnetic storms are primarily driven by the rapid transfer of energy from the solar wind to the magnetosphere. The mechanism of energy transfer involves the merging of the interplanetary magnetic field to the geomagnetic field in a process known as magnetic reconnection. This leads to an influx of energetic, charged particles into the magnetosphere so that current systems are enhanced. Specifically, an increase in the equatorial ring current leads to a decrease in the surface field. Geomagnetic storms are thus characterized by a strong decline in the horizontal components of the geomagnetic field, lasting from several hours to days. The intensity of a storm is described by the disturbed storm-time index, which is essentially a measure of the deviation from the typical quiet day variation along the equator. Severe storms can lead to the disruption of high frequency (HF) communications as a consequence of a strongly perturbed ionosphere. By the same token, the global positioning system (GPS) can become highly unreliable during magnetically disturbed conditions, yielding distance errors as large as 50 meters. The impact of geomagnetic activity and other solar-driven processes on technology systems are collectively known as space weather. Magnetic field sensing thus forms an important part of space weather forecasting and is vital to space science research as a means of improving our understanding of solar wind-magnetosphere interactions. This study examines the use of magnetometers built as SQUIDs (Superconducting Quantum Interference Devices) for monitoring the geomagnetic field for space weather forecasting purposes. A basic theory of superconductivity is presented and subsequently the key aspects governing the operation of SQUIDs are discussed. Space weather is also introduced with respect to the various processes on the sun that perturb the magnetosphere and hence the geomagnetic field. The method of analysis was basically to Fourier-transform the data using the Wiener-Khintchine theorem. A systematic approach to Fourier analysis is thus presented, demonstrating the superiority of the Wiener-Khintchine theorem in noise reduction. The suitability of SQUID magnetometers for space science research is demonstrated by a comparative study between SQUID and fluxgate datasets for magnetic storms during 2011. Strong correlation was observed between the frequency content of the SQUID and fluxgate signals. This result supports South Africa’s SQUID project, currently undertaken as a collaborative effort between SANSA Space Science and the Department of Electrical and Electronic Engineering at Stellenbosch University. This thesis thus lays a foundation for future research involving advanced magnetometry using SQUIDs.
AFRIKAANSE OPSOMMING: Geomagnetiese storms word hoofsaaklik gedryf deur die vinnige oordrag van energie van die sonwind na die magnetosfeer. Die meganisme van energie oordrag behels die samesmelting van die interplanetêre magneetveld met die geomagneetveld, in 'n proses wat bekend staan as magnetiese heraansluiting. Dit lei tot 'n instroming van energieke elektries-gelaaide deeltjies, tot in die magnetosfeer, met die gevolg dat magnetosferiese elektriese stroomstelsels versterk word. 'n Toename in die ekwatoriale ringstrome lei spesifiek tot 'n afname in die horisontale komponent van die geomagnetiese veld. Geomagnetiese storms word dus gekenmerk deur 'n sterk afname in die horisontale komponent van die geomagnetiese veld, ‘n afname wat etlike ure tot dae kan duur. Die intensiteit van 'n storm word beskryf deur die storm-tyd versteurings indeks , 'n maatstaf van die afwyking van die tipiese stil dag magnetiese variasie langs die ewenaar. Ernstige storms kan lei tot die ontwrigting van hoë frekwensie (HF) kommunikasie as 'n gevolg van 'n erg versteurde ionosfeer. Soortgelyk kan die Globale Posisionering Stelsel (GPS) hoogs onbetroubaar word tydens magneties versteurde toestande, en posisiefoute so groot as 50 meter veroorsaak. Die impak van geomagnetiese aktiwiteit en ander sonkrag gedrewe prosesse op tegnologie is gesamentlik bekend as ruimteweer. Magneetveldmetinge vorm dus 'n belangrike deel van ruimteweervoorspelling en is noodsaaklik vir ruimtewetenskaplike navorsing as 'n middel om die sonwind-magnetosfeer interaksies beter te verstaan. Hierdie studie ondersoek die gebruik van SQUID (Engels: Superconducting Quantum Interference Device) magnetometers vir die monitering van die geomagnetiese veld vir ruimteweervoorspellingsdoeleindes. ’n Basiese teorie van supergeleiding word aangebied, waarvolgens die sleutelaspekte van SQUIDs bespreek word. Ruimteweer word ook voorgestel in terme van die verskillende prosesse op die son wat die aarde se magnetosfeer en dus die geomagnetiese veld versteur. Die analisemetode wat hier gebruik word, is om die Fourier-transform van data met die Wiener-Khintchine theorema te bereken. A sistematiese metode vir Fourier-analise word aangebied, wat die superiorireit van die Wiener-Khintchine teorema vir ruisvermindering demonstreer. Die geskiktheid van SQUID magnetometers vir ruimtewetenskaplike navorsing word gedemonstreer deur ’n vergelykende studie tussen SQUID- en vloedhek-datastelle vir magnetiese storms gedurende 2011. Sterk korrelasie is waargeneem tussen die frekwensie-inhoud van die SQUID- en vloedhekseine. Hierdie resultate ondersteun Suid-Afrika se SQUID-projek, wat tans as ’n samewerkingspoging tussen SANSA Space Science en die Departement Elektriese en Elektroniese Ingenieurswese aan die Universiteit van Stellenbosch bedryf word. Hierdie tesis lê ’n fondasie vir toekomstige navorsing oor gevorderde magnetometrie met SQUIDs.
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Christlmaier, Evelin Martine. « CC2 response method using local correlation and density fitting approximations for the calculation of the electronic g-tensor of extended open-shell molecules ». Doctoral thesis, Humboldt-Universität zu Berlin, 2021. http://dx.doi.org/10.18452/22835.

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In dieser Arbeit wird eine unrestricted Coupled-Cluster CC2 Response-Methode für die Berechnung von Eigenschaften erster und zweiter Ordnung, mit dem elektronischen g-Tensor als Schwerpunkt, präsentiert. Lokale Korrelations- und Dichtefittingnäherungen wurden verwendet. Die fundamentalen Konzepte notwendig für das Verständnis von Coupled-Cluster-Theorie, Dichtefitting, lokaler Korrelation, allgemeinen Coupled-Cluster Eigenschaften und dem elektronischen g-Tensor werden diskutiert. Die berechneten g-Tensoren werden mit denen durch Coupled-Cluster Singles and Doubles, Dichtefunktionaltheorie und Experiment erhaltenen verglichen. Effizienz und Genauigkeit der Näherung wird untersucht. Ein detailierter Anhang beschreibt die diagrammatische Coupled-Cluster-Theorie sowie ihre Anwendung zur Herleitung der verwendeten Arbeitsgleichungen. Die in dieser Arbeit entwickelte Methode ermöglicht es, den elektronischen g-Tensor von ausgedehnten Systemen mit einer Methode, die nicht auf Dichtefunktionaltheorie basiert, quantitativ vorherzusagen. Damit ist sie ein wichtiger Schritt hin zur Entwicklung von niedrig skalierenden Coupled-Cluster-Methoden höherer Ordnung für diese Art von Problem.
This work presents an unrestricted coupled-cluster CC2 response method using local correlation and density fitting approximations for the calculation of first and second order properties with particular focus on the electronic g-tensor. The fundamental concepts related to coupled-cluster theory, density fitting, local correlation, general coupled-cluster properties and the electronic g-tensor are discussed. The calculated g-tensors are benchmarked against those obtained from coupled-cluster singles and doubles, density functional theory and experiment. Efficiency and accuracy of the approximations is investigated. A detailed appendix covers the fundamentals of diagrammatic coupled-cluster and its application to the derivation of the working equations. The method presented in this thesis enables the quantitative prediction of the electronic g-tensor of extended systems with a method other than density functional theory. It represents an important step towards the development of low-scaling higher order coupled-cluster methods for this type of problem.
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Fischer, Michael. « Non-adiabatic quantum molecular dynamics : - Benchmark systems in strong laser fields - Approximate electron-nuclear correlations ». Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-148848.

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The non-adiabatic quantum molecular dynamics (NA-QMD) method couples self-consistently classical nuclear motion with time-dependent density functional theory (TDDFT) in basis expansion for the electron dynamics. It has become a versatile approach to study the dynamics of atoms, molecules and clusters in a wide range of scenarios. This work presents applications of the NA-QMD method to important benchmark systems and its systematic extension to include quantum effects in the nuclear motion. Regarding the first objective, a complete study of the strong-field ionization and dissociation dynamics of nature’s simplest molecule H2+ is performed. By including all electronic and nuclear degrees of freedom and all reaction channels, molecular rotation is shown to play an important role in the ionization process. In addition, strong orientation effects in the energy deposition process of the Buckminster fullerene C60 in short intense laser pulses are surprisingly found in full dimensional calculations. Their consequences on the subsequent nuclear relaxation dynamics shed new light on available experimental data and future experiments are proposed to confirm the detailed predictions. Regarding the second objective, the NA-QMD formalism is basically extended to take electron-nuclear correlations into account. This extension is achieved by means of a trajectory surface hopping scheme in the adiabatic Kohn-Sham framework. First studied examples from collision physics and photochemistry illustrate the relevance and importance of quantum effects in the nuclear dynamics.
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Anacker, Tony. « Incremental Scheme for Open-Shell Systems ». Doctoral thesis, Universitätsbibliothek Chemnitz, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-197726.

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In this thesis, the implementation of the incremental scheme for open-shell systems with unrestricted Hartree-Fock reference wave functions is described. The implemented scheme is tested within robustness and performance with respect to the accuracy in the energy and the computation times. New approaches are discussed to implement a fully automated incremental scheme in combination with the domain-specific basis set approximation. The alpha Domain Partitioning and Template Equalization are presented to handle unrestricted wave functions for the local correlation treatment. Both orbital schemes are analyzed with a test set of structures and reactions. As a further goal, the DSBSenv orbital basis sets and auxiliary basis sets are optimized to be used as environmental basis in the domain-specific basis set approach. The performance with respect to the accuracy and computation times is analyzed with a test set of structures and reactions. In another project, a scheme for the optimization of auxiliary basis sets for uranium is presented. This scheme was used to optimize the MP2Fit auxiliary basis sets for uranium. These auxiliary basis enable density fitting in quantum chemical methods and the application of the incremental scheme for systems containing uranium. Another project was the systematical analysis of the binding energies of four water dodecamers. The incremental scheme in combination with the CCSD(T) and CCSD(T)(F12*) method were used to calculate benchmark energies for these large clusters.
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Lombardo, Pierre. « Théorie de champ moyen dynamique appliquée à l'étude des propriétés électroniques des oxydes de métaux de transition ». Université Joseph Fourier (Grenoble ; 1971-2015), 1997. http://www.theses.fr/1997GRE10161.

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Nous avons propose une approche susceptible d'expliquer de nombreuses proprietes electroniques des materiaux dont les porteurs de charge sont soumis a de fortes correlations. Parmi les materiaux consideres, citons en particulier les supraconducteurs a haute temperature critique et les oxydes de metaux de transition de type perovskite. L'approche developpee dans cette these est une extension de la theorie de champ moyen dynamique a des systemes electroniques a plus de un degre de liberte orbital. Elle est basee sur une nouvelle procedure de renormalisation du modele de hubbard a deux bandes pour l'extension aux grandes dimensions spatiales de la structure perovskite. Un traitement selectif des differents processus de sauts entre sites de metal de transition (mt) et d'oxygene (o) plus proche voisins, nous a permis de conserver de nombreux aspects dynamiques non triviaux dans cette limite. Le probleme sur reseau est projete sur un modele d'impurete de type anderson. La solution du probleme local a ete obtenue par la theorie des perturbations iterees et par une extension de l'approximation de non-crossing (nca). La technique de nca nous a permis de decrire correctement d'importantes proprietes spectrales des oxydes de metaux de transition, donnant des informations tres interessantes sur la nature des differentes bandes des densites d'etats du metal de transition et de l'oxygene, et sur leur comportement en fonction du dopage. De plus, le pic coherent de quasiparticule, proche du niveau de fermi, a ete obtenu. Ce pic presente d'interessantes variations en fonction du dopage, mais aussi de la temperature. Ces excitations de basse energie proviennent de resonances de type kondo, entre l'etat vide et un etat hybride mt-o dans le cas du dopage en electrons, et entre cet etat mt-o et un etat singulet de type zhang et rice dans le cas du dopage en trous. L'application de notre approche nca a des familles de materiaux reels comme lamo#3 ou ca#1##xsr#xvo#3 a mis en evidence l'importance fondamentale des excitations a transfert de charge dans ces composes. Une description correcte des proprietes electroniques des oxydes de metaux de transition peut donc etre donnee par une approche de champ moyen dynamique mais necessite la prise en compte a la fois des etats de l'oxygene et de ceux du metal de transition.
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Gorceix, Olivier. « Effet du terme de breit complet sur les niveaux d'energie des atomes : applications au cas des ions lourds heliumoides ». Paris 6, 1987. http://www.theses.fr/1987PA066403.

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Mise au point d'un programme de calcul des elements de matrice de l'operateur de retard relativiste pour etudier l'influence du terme complet de breit exprime en jauge de lorentz, sur l'energie des niveaux atomiques. Lois d'echelle demontrant l'importance numerique des termes relativistes d'ordre eleve pour les ions a 2 electrons. Demonstration de l'influence de la jauge sur les valeurs moyennes du terme complet de breit, lorsqu'elles sont prises sur des fonctions autocoherentes du modele de dirac-fock. Par la methode mcdf, mise en evidence des correlations magnetiques et d'une contribution relativiste dans les correlations electrostatiques; valeurs de ces correlations pour le niveau fondamental et des niveaux 1s2p. Etude des effets du terme de breit sur la structure fine 1s2p dans le domaine relativiste: le terme magnetique induit une inversion des niveaux de j=0 et du niveau profond de j=1 par rapport aux previsions non relativistes
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Rérat, Michel. « Methode invariante de jauge pour le calcul de proprietes magnetiques : applications a de petites molecules ». Paris 6, 1987. http://www.theses.fr/1987PA066024.

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Developpement d'une technique de calcul des proprietes magnetiques qui combine les avantages des methodes classiques tenant compte de la correlation electronique et qui conserve l'invariance de jauge de la methode des polynomes par un systeme de compensation interne. Calcul des corrections rovibroniques, decrites analytiquement par la methode des perturbation, pour des molecules diatomiques (h::(2), co) pour une comparaison des resultats theoriques et experimentaux
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Fischer, Michael. « Non-adiabatic quantum molecular dynamics : - Benchmark systems in strong laser fields - Approximate electron-nuclear correlations : Non-adiabatic quantum molecular dynamics : - Benchmark systems in strong laser fields - Approximate electron-nuclear correlations ». Doctoral thesis, 2013. https://tud.qucosa.de/id/qucosa%3A28198.

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The non-adiabatic quantum molecular dynamics (NA-QMD) method couples self-consistently classical nuclear motion with time-dependent density functional theory (TDDFT) in basis expansion for the electron dynamics. It has become a versatile approach to study the dynamics of atoms, molecules and clusters in a wide range of scenarios. This work presents applications of the NA-QMD method to important benchmark systems and its systematic extension to include quantum effects in the nuclear motion. Regarding the first objective, a complete study of the strong-field ionization and dissociation dynamics of nature’s simplest molecule H2+ is performed. By including all electronic and nuclear degrees of freedom and all reaction channels, molecular rotation is shown to play an important role in the ionization process. In addition, strong orientation effects in the energy deposition process of the Buckminster fullerene C60 in short intense laser pulses are surprisingly found in full dimensional calculations. Their consequences on the subsequent nuclear relaxation dynamics shed new light on available experimental data and future experiments are proposed to confirm the detailed predictions. Regarding the second objective, the NA-QMD formalism is basically extended to take electron-nuclear correlations into account. This extension is achieved by means of a trajectory surface hopping scheme in the adiabatic Kohn-Sham framework. First studied examples from collision physics and photochemistry illustrate the relevance and importance of quantum effects in the nuclear dynamics.
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Livres sur le sujet "Electronic Correlation Theories"

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Kostyukov, Viktor. Theory of quantum chemistry. ru : INFRA-M Academic Publishing LLC., 2021. http://dx.doi.org/10.12737/1090584.

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The textbook summarizes the basic theories of quantum chemistry. A comparative analysis of the computational efficiency of computational algorithms implementing these theories from the point of view of the ratio "accuracy — resource intensity" is performed. Considerable attention is paid to the problem of accounting for electronic correlation, as well as relativistic quantum chemical effects. Meets the requirements of the federal state educational standards of higher education of the latest generation. It is intended for undergraduate students of higher educational institutions; it can be used by graduate students studying materials science, structural, organic and physical chemistry, molecular biology and biophysics, biotechnology.
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Chapitres de livres sur le sujet "Electronic Correlation Theories"

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Campbell, C. E., Tao Pang et E. Krotscheck. « Electron Correlations in Atoms ». Dans Condensed Matter Theories, 265–71. Boston, MA : Springer US, 1990. http://dx.doi.org/10.1007/978-1-4613-0605-4_28.

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Neilson, D., L. Świerkowski et J. Szymański. « Correlations in Coupled Electron Layers ». Dans Condensed Matter Theories, 61–69. Boston, MA : Springer US, 1993. http://dx.doi.org/10.1007/978-1-4615-2934-7_6.

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Fulde, Peter. « Electron Correlations in Different Electron Bonds ». Dans Recent Progress in Many-Body Theories, 69–73. Boston, MA : Springer US, 1988. http://dx.doi.org/10.1007/978-1-4613-0973-4_7.

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Mayer, István. « The Electron Correlation ». Dans Simple Theorems, Proofs, and Derivations in Quantum Chemistry, 251–80. Boston, MA : Springer US, 2003. http://dx.doi.org/10.1007/978-1-4757-6519-9_8.

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March, N. H. « Localized versus Molecular Orbital Theories of Electrons ». Dans Electron Correlation in Molecules and Condensed Phases, 47–74. Boston, MA : Springer US, 1996. http://dx.doi.org/10.1007/978-1-4899-1370-8_4.

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Levy, Mel. « On Time-Independent Density-Functional Theories for Excited States ». Dans Electron Correlations and Materials Properties, 299–308. Boston, MA : Springer US, 1999. http://dx.doi.org/10.1007/978-1-4615-4715-0_19.

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Vibók, Ágnes, Gábor J. Halász et István Mayer. « Bsse-Corrected Perturbation Theories of Intermolecular Interactions ». Dans Electron Correlations and Materials Properties 2, 263–83. Boston, MA : Springer US, 2002. http://dx.doi.org/10.1007/978-1-4757-3760-8_15.

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Hafermann, Hartmut, Frank Lechermann, Alexei N. Rubtsov, Mikhail I. Katsnelson, Antoine Georges et Alexander I. Lichtenstein. « Strong Electronic Correlations : Dynamical Mean-Field Theory and Beyond ». Dans Modern Theories of Many-Particle Systems in Condensed Matter Physics, 145–214. Berlin, Heidelberg : Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-10449-7_4.

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Oleś, Andrzej M., et Jan Zaanen. « Strong Electron Correlations in C u O 2 Planes of HighTemperature Superconductors ». Dans Recent Progress in Many-Body Theories, 55–64. Boston, MA : Springer US, 1990. http://dx.doi.org/10.1007/978-1-4615-3798-4_7.

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Neilson, D., F. Green et J. Szymański. « Dynamic Correlations in the Electron Gas : The Mean Field Picture and Beyond ». Dans Recent Progress in Many-Body Theories, 235–43. Boston, MA : Springer US, 1988. http://dx.doi.org/10.1007/978-1-4613-0973-4_24.

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Actes de conférences sur le sujet "Electronic Correlation Theories"

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Bastawros, Ashraf, et Antonia Antoniou. « Deformation Characteristics of Solder Joints ». Dans ASME 2003 International Electronic Packaging Technical Conference and Exhibition. ASMEDC, 2003. http://dx.doi.org/10.1115/ipack2003-35078.

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A novel experimental configuration is devised to measure the evolution of the deformation field and the corresponding toughness in solder joints for microelectronic packaging. The material system utilized comprised ductile layer of Tin based solder, encapsulated within relatively hard copper shoulders. The experimental configuration provides pure shear state within the constrained solder layer. Different Pb/Sn compositions are tested with grain size approaching the film thickness. The in-plan strain distribution within the joint thickness is measured by a microscopic digital image correlation system. The toughness evolution within such highly gradient deformation field is monitored qualitatively through a 2D surface scan with a nano-indentor. The measurements showed a highly inhomogeneous deformation field within the film with discreet shear bands of concentrated strain. The localized shear bands showed long-range correlations of the order of 2–3 grain diameter. A size-dependent macroscopic response on the layer thickness is observed. However, the corresponding film thickness is approximately 100–1000 times larger than those predicted by non-local continuum theories and discreet dislocation.
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Osoekawa, Takeshi, Naoyuki Shinohara, Yuji Mochizuki et Kazuhiro Yokoyama. « Gröbner Basis Technique for Algebraic Formulas in Electron Correlation Theories ». Dans 2010 International Conference on Computational Science and Its Applications. IEEE, 2010. http://dx.doi.org/10.1109/iccsa.2010.30.

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Herescu, Alexandru, et Jeffrey S. Allen. « The Effect of Surface Wettability on Viscous Film Deposition ». Dans ASME 2009 7th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2009. http://dx.doi.org/10.1115/icnmm2009-82263.

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The viscous deposition of a liquid film on the inside of a capillary has been experimentally investigated with a focus on the relationship between the film thickness and surface wettability. With distilled water as a working fluid tests were run in a 622 microns diameter glass tube with contact angles of 30° and 105°, respectively. In the first set of experiments the tube was uncoated while in the second set a fluoropolymer coating was applied to increase the contact angle. A film thickness dependence with the contact angle θ (surface wettability) as well as the Capillary number in the form hR ∼ Ca2/3/cosθ is inferred from scaling arguments. For partial wetting it may explain the existence of a thicker film for nonzero contact angle. It was further found that the non-wetting case of 105° contact angle deviates significantly from the existing theories, the film thickness presenting a weak dependence with the Capillary number. This deviation as well as the apparent non-uniqueness of the solution is thought to be caused by the film instability (rupture) observed during the tests. The thickness of the deposited film as a function of the Capillary number was estimated from the liquid mass exiting the capillary and the gas-liquid interface (meniscus) velocity, and compared to Bretherton’s data and a correlation proposed by Quere. The film thickness measurements as well as the meniscus velocity were determined with the aid of a Photron high speed camera with 10000 frames per second sampling capability coupled with a Nikon TE-2000 inverted microscope and a Precisa electronic balance.
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« How Content Volume on Landing Pages Influences Consumer ‎‎Behavior : Empirical Evidence ». Dans InSITE 2018 : Informing Science + IT Education Conferences : La Verne California. Informing Science Institute, 2018. http://dx.doi.org/10.28945/4016.

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Aim/Purpose: This paper describes an empirical investigation on how consumer behavior is influenced by the volume of content on a commercial landing page -- a stand-alone web page designed to collect user data (in this case the user’s e-mail address), a behavior called “conversion.” Background: Content is a term commonly used to describe the information made available by a website or other electronic medium. A pertinent debate among scholars and practitioners relate to information volume and consumer behavior: do more details elicit engagement and compliance, operationalized through conversions, or the other way around? Methodology: A pilot study (n= 535) was conducted in ‎real-world commercial setting, followed by a series of large-scale online experiments (n= 27,083). Both studies employed a between-group design: Two variations of landing pages, long and short, were created based on various behavioral theories. User traffic to the pages was generated using online advertising and randomized between the pages (A/B testing). Contribution: This research contributes to the body of knowledge on the antecedents and outcomes of online commercial interaction, focusing on content as a determinant of consumer decision-making and behavior. Findings: The observed results indicate a negative correlation between content volume and users’ conversions. The shorter pages had significantly higher conversion rates, across locations and time. Findings suggest that content play a significant role in online decision making. They also contradict prior research on trust, persuasion, and security. Recommendations for Practitioners: At a practical level, results can inform practitioners on the importance of content in online commerce. They provide an empirical support to design and content strategy considerations, specifically the use of elaboration in commercial web pages. Recommendation for Researchers: At the theoretical level, this research advances the body of knowledge on the paradoxical relationship between the increased level of information and online decision-making and indicates that contrary to earlier work, not all persuasion theories‎ are ‎effective online. Impact on Society: Understanding how information drive behavior has implications in many domains (civic engagement, health, education and more). This has relevance to system design and public communication in both online and offline contexts, suggesting social value. Future Research: ‎Using this research as a starting point, future research can examine the impact of content in other contexts, as well as other behavioral drivers (such as demographic data). This can lead to theoretical, methodological and practical recommendations.
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Fleury, P. A., et K. B. Lyons. « Light scattering from spin and electronic excitations in Tc superconductors ». Dans OSA Annual Meeting. Washington, D.C. : Optica Publishing Group, 1988. http://dx.doi.org/10.1364/oam.1988.tuj2.

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The high-temperature superconductors now fall into several structural and compositional classes. However, they all are oxides of copper, show little or no isotope effect, are relatively poor metals in their normal state, have very low carrier densities, and are closely related in composition to compounds which exhibit magnetic order. All of these attributes, together of course with the very high values of Tc, strongly suggest that the heretofore very successful microscopic theory of superconductivity based on the electron-photon interaction is inadequate here. Alternative theories have now appeared which invoke excitons, plasmons, polarons, magnons, or other pairing mediators. Recently inelastic light scattering has provided direct observation of the spin and electronic excitation spectra in single crystals of the superconducting cuprates and their insulating magnetically ordered relatives. This paper reviews these observations. Particular emphasis is given to the spin fluctuations which typically are characterized by quite high (~1000-cm-1) exchange energies and their behavior with temperature and composition. Correlations between the spin fluctuation spectra and Tc are described. In addition evidence for a superconducting energy gap is presented as is the influence of electron-phonon interactions on Raman line shapes. The relationships of all these results to candidate theories for high Tc superconductivity are discussed.
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Oates, William S. « Correlations Between Quantum Mechanics and Continuum Mechanics for Ferroelectric Material Simulations ». Dans ASME 2013 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/smasis2013-3184.

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Higher order effects in ferroelectric materials are investigated by integrating electron density calculations using quantum mechanics into a homogenized, nonlinear continuum modeling framework. Electrostatic stresses based on the Hellmann-Feynman theorem are used to identify connections with the higher order quadrupole density. These higher order relations are integrated into a nonlinear mechanics free energy function to simulate electromechanical coupling. A specific example is investigated by conducting density functional theory (DFT) calculations on barium titanate and fitting the results to a thermodynamic potential function. Through the use of nonlinear geometric effects, electromechanical coupling is obtained without the use of electrostrictive or piezoelectric coupling coefficients.
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Rackers, Joshua. « What can machine learning and the Hellmann-Feynman Theorem teach us about the limits of electron correlation?. » Dans Proposed for presentation at the American Chemical Society Fall Meeting in , . US DOE, 2021. http://dx.doi.org/10.2172/1884141.

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Binder, R., K. Henneberger, F. Herzel, S. W. Koch, A. E. Paul et D. Scott. « Optical dephasing and spectral hole burning in semiconductor lasers ». Dans OSA Annual Meeting. Washington, D.C. : Optica Publishing Group, 1991. http://dx.doi.org/10.1364/oam.1991.tutt4.

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Theoretical studies of spectral hole burning in semiconductors lasers require two equally important ingredients: (i) the dynamics of the coupled carrier-photon system and (ii) a microscopical description of the carrier–carrier scattering. The first point is common to all laser theories, where the laser field (given as classical field amplitude or indirectly as a quantum-mechanical expectation value of field-correlation functions) is driven by the polarization of the semiconductor. The material polarization is essentially determined by the carrier inversion (i.e., the distribution functions of electrons and holes), and thus, by microscopical carrier–carrier scattering processes. The scattering affects the lasing process in a twofold way. First, it yields a refilling of the carrier states emptied by stimulated emission, and second, it leads to a decay of the polarization (dephasing). Thus, a possible spectral hole in the probe spectrum of a laser is itself crucially influenced by the carrier kinetics and the polarization decay. We evaluate a set of equations consistently describing the field (in terms of correlation functions) and material properties for continuously pumped single-mode short cavity laser.
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Kim, Ook Joong, Young-Ho Choi et Seok Ho Yoon. « Flow Characteristics of Electronic Expansion Valves for Heat Pump System Using Carbon Dioxide as a Refrigerant ». Dans ASME 2010 3rd Joint US-European Fluids Engineering Summer Meeting collocated with 8th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2010. http://dx.doi.org/10.1115/fedsm-icnmm2010-30415.

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An experimental study on the flow characteristics of electronic expansion valves (EEVs) for heat pump system using carbon dioxide as a refrigerant have been carried out in this study. Many researches and efforts have been made to replace chemical refrigerants like Chloro-Fluoro-Carbon (CFC) and Hydro-Chloro-Fluoro-Carbon (HCFC) with natural refrigerants such as carbon dioxide and apply natural refrigerants to chillers or heat pump systems. In this study, we focused on the development of EEV and 4-way valve among the important components of heat pump system using natural refrigerant. The mass flow rate was measured at various EEV inlet temperature and pressure conditions with respect to several EEV openings operated at a heat pump system which has about 10 kW of cooling capacity. The heat pump system consists of a reciprocating compressor, a gas cooler, an evaporator, an EEV, and a 4-way valve which was developed for this study. The inlet temperature and pressure of an EEV was varied from 5°C to 40°C and from 7 MPa to 10 MPa, respectively. The mass flow rate of carbon dioxide through the EEV ranged from 50 g/s to 120 g/s. The mass flow rate of carbon dioxide around the critical point was affected by the inlet temperature and pressure of EEV, valve opening, and density variation. An empirical mass flow rate correlation of carbon dioxide based on the Buckingham π-theorem was developed in this study, and this correlation predicted experimental data within an average absolute deviation of 4.2%. The correlation can be applied to predict the mass flow rate through EEV used in the heat pump system using carbon dioxide as a refrigerant. And the reliability test of developed 4-way valve was conducted. This 4-way valve showed stable operation in the high pressure condition.
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Gamo, Hideya. « Physical optics of electron waves : wave impedance and coherence ». Dans OSA Annual Meeting. Washington, D.C. : Optica Publishing Group, 1987. http://dx.doi.org/10.1364/oam.1987.thf10.

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The advanced technology of electron microscope has recently achieved Dennis Gabor's original concept of holographic reconstruction of electron microscope images.1 This is due to the improved coherence property of electron waves and optical holography. This stimulated me to reexamine the analogy of electron waves and electromagnetic waves and clarify its physical meaning. First, the characteristic wave impedance of electron wave η e is defined by the ratio of the Schrodinger wave function ψ and then the associated momentum state function ϕ: η e = E / 2 m , where E is the energy of electron and m is the mass or effective mass of an electron in either free space or solid-state materials. Note that the phase constant β = 2 M E / ℏ and the refractive index is defined by the ratio β. Second, using the boundary conditions consisting of continuity of both ψ and ϕ, we obtain the reflection and transmission coefficients for the obliquely incident electron wave. These coefficients correspond to those of the s wave of TE waves in electromagnetic optics. Total internal reflection exists, but the Brewster angle is missing in electron optics. The coherence theory of electron waves such as the Van Cittert-Zernike theorem and the intensity correlation are also discussed.
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Rapports d'organisations sur le sujet "Electronic Correlation Theories"

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So Hirata. Final Scientific/Technical Report : Breakthrough Design and Implementation of Many-Body Theories for Electron Correlation. Office of Scientific and Technical Information (OSTI), janvier 2012. http://dx.doi.org/10.2172/1032501.

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Cox, Daniel L. Final Report on ``Theories of Strong Electron Correlations in Molecules and Solids-DE-FG02-97ER45640. Office of Scientific and Technical Information (OSTI), avril 2013. http://dx.doi.org/10.2172/1073633.

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