Sökning: "Conical intersections"

Hittade 5 avhandlingar innehållade orden Conical intersections.

  1. 1. Non-linear Spectroscopy of Conical Intersections with XUV and X-ray Photons

    Författare :Deependra Jadoun; Markus Kowalewski; Faris Gelmukhanov; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Conical Intersections; Non-linear Spectroscopy; Quantum Dynamics; Perturbation Theory; Ultrafast Spectroscopy; X-ray; XUV; Theoretical Physics; teoretisk fysik;

    Sammanfattning : Conical intersections (CIs) appear in a molecule due to the breakdown of the Born-Oppenheimer approximation when the energy difference between two or more electronic states decreases. CIs are known to play a crucial role in processes such as photosynthesis and vision in the human eye, and therefore it is important to probe the existence of such entities in molecules. LÄS MER

  3. 2. Non-linear Spectroscopy of Conical Intersections

    Författare :Deependra Jadoun; Markus Kowalewski; Eva Lindroth; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; kemisk fysik; Chemical Physics;

    Sammanfattning : Conical Intersections (CIs) in a molecule originate from the breakdown of the Born-Oppenheimer approximation when electronic states come close in energy. Ultrafast non-radiative decay channels open up in the vicinity of a CI, thus funneling a molecule from one electronic state to another. LÄS MER

  4. 3. Photo-induced molecular processes and charge recombination reactions driven by non-adiabatic couplings

    Författare :Michael Stenrup; Åsa Larson; Horst Köppel; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Non-adiabatic processes; Photophysics; Photochemistry; Radiationless deactivation; Conical intersections; Five-membered aromatic heterocyclic compounds; Mutual neutralization; Dissociative recombination; kemisk fysik; Chemical Physics;

    Sammanfattning : This thesis is based on a number of theoretical studies of molecular processes in which non-adiabatic effects play a crucial role. The main part is devoted to the photophysics and photochemistry of five-membered aromatic heterocyclic compounds, with particular focus on furan and thiophene. LÄS MER

  5. 4. Coupling mechanisms in scattering reactions involving small molecular systems

    Författare :Patrik Hedvall; Åsa Larson; Magnus Gustafsson; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Theoretical Physics; teoretisk fysik;

    Sammanfattning : In this thesis, theoretical ab initio treatments of two-body molecular collision reactions are studied, having in common that the interaction region including all coupling mechanisms driving the reaction amounts to a molecular description. The main goal is to gain an understanding in the underlying coupling mechanisms involved in these reactions. LÄS MER

  7. 5. 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