Sökning: "double excitations"

Visar resultat 1 - 5 av 18 avhandlingar innehållade orden double excitations.

1. 1. Double Excitations in Helium Atoms and Lithium Compounds

   Författare :Marcus Agåker; Jan-Erik Rubensson; Leif Karlsson; David Ederer; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Atomic and molecular physics; Soft X-ray emission; resonant inelastic X-ray scattering; double excitations; lithium halide; helium; Atom- och molekylfysik;

   Sammanfattning : This thesis addresses the investigation of doubly excited 2l´nl states in helium atoms and double core excitations in solid lithium compounds.Measurements on He are made in field free environments and under the influence of electric and magnetic fields, using synchrotron based inelastic photon scattering. LÄS MER

3. 2. Soft X-ray Scattering Dynamics Close to Core Ionization Thresholds in Atoms and Molecules

   Författare :Johan Söderström; Jan-Erik Rubensson; Lorenzo Avaldi; Uppsala universitet; []
   Nyckelord :Physics; Soft X-ray emission; Resonant inelastic X-ray scattering; Double excitations; Helium; X-ray-emission-threshold-electron coincidence; Fysik;

   Sammanfattning : In this Thesis studies of highly excited states in gas-phase atoms and molecules (He, Ne, N2, O2, N2O and CO2) using a variety of synchrotron-radiation based techniques are presented. The three techniques used most frequently are X-ray-emission-threshold-electron coincidence (XETECO), X-ray emission spectroscopy (XES) and X-ray photoelectron spectroscopy (XPS) and they are all given a brief introduction. LÄS MER

4. 3. Precision molecular spectroscopy in the near- and mid-infrared using frequency comb-based Fourier transform spectrometers

   Författare :Adrian Hjältén; Aleksandra Foltynowicz; Ove Axner; Adam Fleisher; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; optical frequency comb; molecular spectroscopy; Fourier transform spectrometer; high resolution; mid-infrared; line list; double-resonance spectroscopy; difference frequency generation; fysik; Physics;

   Sammanfattning : Absorption spectroscopy is a powerful scientific tool for non-invasive and remote sensing applications ranging from atmospheric monitoring to astrophysics. In spectroscopic detection schemes it is necessary to have spectral models for any molecular species to be detected or quantified. LÄS MER

5. 4. Studies of Single and Multiple Ionization Processes in Rare Gases and some Small Molecules

   Författare :Lage Hedin; Raimund Feifel; Dag Hanstorp; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik; Physics with spec. in Atomic; Molecular and Condensed Matter Physics;

   Sammanfattning : In this thesis various aspects of photoionization are investigated with respect to both single and multiple electron emission from atoms and molecules. The studies include both valence and core levels and involve transitions which leave the atoms or molecules in various charge states. LÄS MER

7. 5. Bose-Einstein Condensation of Magnetic Excitons in Semiconductor Quantum Wells

   Författare :Vitalie Boţan; Lars Nordström; Sveatoslav Moskalenko; Pavlos Lagoudakis; Uppsala universitet; []
   Nyckelord :Physics; Bose-Einstein condensation; magnetic excitons; electron-hole pairs; electron-hole liquid; magnetorotons; magnetoplasmons; superfluidity; Fysik;

   Sammanfattning : In this thesis regimes of quantum degeneracy of electrons and holes in semiconductor quantum wells in a strong magnetic field are studied theoretically. The coherent pairing of electrons and holes results in the formation of Bose-Einstein condensate of magnetic excitons in a single-particle state with wave vector K. LÄS MER