Sökning: "Ehrenfest Dynamics"

Hittade 5 avhandlingar innehållade orden Ehrenfest Dynamics.

  1. 1. Theoretical perspectives on ultrafast and non-linear spectroscopy

    Författare :Emil Vinas Boström; Matematisk fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Non-linear optics; Ultrafast dynamics; Non-equilibrium Green s functions; Density functional theory; Multi-photon absorption; Second harmonic generation; Desorption dynamics; Auger decay; Charge-separation dynamics; Quantum Zeno effect; Fysicumarkivet A:2018:Vinas Boström;

    Sammanfattning : In this thesis we discuss a theoretical description of ultrafast and non-linear spectroscopy. Due to the high intensities and ultrashort pulse durations involved in such experiments, it is necessary to use an explicitly time-dependent formalism. LÄS MER

  3. 2. Numerical Methods for Molecular Dynamics with Nearly Crossing Potential Surfaces

    Författare :Ashraful Kadir; Anders Szepessy; Emanuel Rubensson; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Numerical Methods; Molecular Dynamics; Nearly Crossing Potential Surfaces; Error Estimation; Adaptive Algorithm; Tillämpad matematik och beräkningsmatematik; Applied and Computational Mathematics;

    Sammanfattning : This thesis consists of four papers that concern error estimates for the Born-Oppenheimer molecular dynamics, and adaptive algorithms for the Car-Parrinello and Ehrenfest molecular dynamics.In Paper I, we study error estimates for the Born-Oppenheimer molecular dynamics with nearly crossing potential surfaces. LÄS MER

  4. 3. Theoretical Developments for the Real-Time Description and Control of Nanoscale Systems

    Författare :Miroslav Hopjan; Matematisk fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Green’s Function; DFT; TDDFT; Hubbard Model; Many-Body Perturbation Theory; Strongly Correlated Systems; Quantum Transport; Disorder; Ehrenfest Dynamics; Electronic Friction; Exact Diagonalization; Periodic Anderson Model; Fysicumarkivet A:2018:Hopjan;

    Sammanfattning : In this thesis we focus on improvements of the description of the electron-electron correlation effects in nonequilibrium nanosystems. We mainly focus on developments of two nonequilibrium methods, namely the formalism of Nonequilibrium Green’s Function and Time Dependent Density Functional Theory and we explore the possibility to improve existing approximations in these theories. LÄS MER

  5. 4. Multiscale models and simulations for diffusion and interaction in heterogeneous domains

    Författare :Omar Malcolm Richardson; Adrian Muntean; Björn Engquist; Karlstads universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; multiscale modeling; finite element methods; interacting particle sytems; population dynamics; non-equilibrium dynamics; Matematik; Mathematics;

    Sammanfattning : We investigate multiscale and multiphysics models for evolution systems in heterogeneous domains, with a focus on multiscale diffusions. Although diffusion is often studied in terms of continuum observables, it is a consequence of the motion of individual particles. LÄS MER

  7. 5. Error Estimation and Adaptive Methods for Molecular Dynamics

    Författare :Ashraful Kadir; Anders Szepessy; Emanuel Rubensson; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : This  thesis consists of two  papers that  concern error estimates for the Born-Oppenheimer molecular dynamics, and adaptive algorithms for the Car-Parrinello and Ehrenfest molecular dynamics. In Paper I, we study error estimates for Born-Oppenheimer molecular dynamics with  nearly crossing potential  surfaces. LÄS MER