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Visar resultat 1 - 5 av 46 avhandlingar som matchar ovanstående sökkriterier.

1. 1. Algorithms for Molecular Dynamics Simulations

   Författare :Fredrik Hedman; Aatto Laaksonen; Tom Darden; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; molecular dynamics; MD; first principles molecular dynamics; quantum mechanics; liquid water; parallel algorithm; data parallel; MPI; Coulombic interaction; Ewald summation; nonuniform fast Fourier transform; FFT; FFTW; NFFT; ENUF; Physical chemistry; Fysikalisk kemi;

   Sammanfattning : Methods for performing large-scale parallel Molecular Dynamics(MD) simulations are investigated. A perspective on the field of parallel MD simulations is given. Hardware and software aspects are characterized and the interplay between the two is briefly discussed. LÄS MER

3. 2. Magnetization dynamics on the nanoscale : From first principles to atomistic spin dynamics

   Författare :Jonathan Philippe Chico Carpio; Anders Bergman; Samir Lounis; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

   Sammanfattning : In this thesis first-principles methods, based on density functional theory, have been used to characterize a wide range of magnetic materials. Special emphasis has been put on pairwise magnetic interactions, such as Heisenberg exchange and Dzyaloshinskii-Moriya interactions, and also on in the Gilbert damping parameter. LÄS MER

4. 3. Effects of disorder in metallic systems from First-Principles calculations

   Författare :Christian Asker; Igor Abrikosov; Jörg Neugebauer; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Iron; Nickel; Magnesium; Manganese; Molybdenum; Zirconium; Elastic Constants; High pressure; Earth s core; Density-functional theory; Ab-initio; First-Principles; Core-level shifts; Molecular Dynamics; Phonons; Dynamical Instability; Condensed matter physics; Kondenserade materiens fysik; Computational physics; Beräkningsfysik;

   Sammanfattning : In this thesis, quantum-mechanical calculations within density-functional theory on metallic systems are presented. The overarching goal has been to investigate effects of disorder. In particular, one of the properties investigated is the bindingenergy shifts for core electrons in binary alloys using different theoretical methods. LÄS MER

5. 4. Quantum transport and geometric integration for molecular systems

   Författare :Anders Odell; Anna Delin; Anders Niklasson; Michael Springborg; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; density functional theory; ab initio; first principles; electron transport; photoswitching; molecular dynamics; geometric integration; Condensed matter physics; Kondenserade materiens fysik; Computational physics; Beräkningsfysik;

   Sammanfattning : Molecular electronics is envisioned as a possible next step in device miniaturization. It is usually taken to mean the design and manufacturing of electronic devices and applications where organic molecules work as the fundamental functioning unit. LÄS MER

7. 5. Structural and magnetic disorder in crystalline materials : a first principles study

   Författare :Davide Gambino; Björn Alling; Pavel Korzhavyi; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : Disorder in crystalline materials can take different forms and originate from different sources. In particular, temperature introduces disorder in any kind of material. LÄS MER