Free electron model

About: Free electron model is a research topic. Over the lifetime, 4678 publications have been published within this topic receiving 103535 citations.

Theoretical investigation of pulsed microwave discharge in nitrogen

Abstract: A pulsed microwave discharge burning close to the centre of a cylindrical chamber (/2 = 2.45 GHz) in pure nitrogen at low pressure (5 mbar) has been investigated theoretically. Boltzmann equation analysis is applied for the description of the breakdown and the consecutive maintenance phase of the discharge. The breakdown electric field is estimated using the calculated ionization frequency and the losses by the free electron diffusion. A self-consistent model for electron and heavy-particle kinetics coupling the rate master equations for the vibrational levels N2(X,v) of the electronic ground state of the nitrogen molecule to the Boltzmann equation of electrons has been developed. Besides the momentum transfer, inelastic as well as superelastic e-V collisions, ionization and free diffusion of electrons have been taken into account in the Boltzmann equation. The balance of the populations of the vibrational levels includes e-V, V-V and V-T exchanges, dissociation, atom re-association, vibrational deactivation on the walls and the effect of molecular diffusion. A further relation used is the global energy balance of electrons. The calculated breakdown electric field strength and the temporal course of the population of vibrational levels have been compared with experimental breakdown data and CARS measurements. Calculations and measurements are found to agree well.

Fermi surface of the ferromagnetic heavy-electron compound UGe2

Abstract: In the itenerant 5f electron model, the Fermi surface is derived phenomenologically for the heavy-electron ferromagnet UGe2 using a relativistic APW method The main de Haas-van Alphen frequencies together with the cyclotron effective masses can be explained reasonably well

Photon-photon angular correlations in the radiative recombination of bare high-Z ions

Abstract: The radiative recombination of a free electron into excited states of bare, high-Z ions and the subsequent photon decay are studied in the framework of the density matrix theory. Emphasis is placed, in particular, on the angular correlation between the recombination and the decay photons. The general expression for the photon–photon angular correlation function is derived, based on Dirac's equation as appropriate for high-Z ions. Computations for the dependence of the photon–photon correlation function on the nuclear charge and the projectile energies are carried out for the capture into the 2p3/2 level and the subsequent Lyman-α1 (2p3/2 → 1s1/2) radiation.

Observation of the Relative Polarizations of Electronic Transitions

Abstract: The polarization of fluorescence of several aromatic systems in a rigid glass of propylene glycol at —78°C has been determined. Polarized exciting radiation absorbed in a single electronic band was used, enabling the determination of the polarization of higher electron transitions relative to that of the lowest singlet‐singlet transition. Results are in agreement with current theoretical ideas for anthracene and several of its derivatives. Results for peri‐condensed systems suggest the need for a more thorough examination of the free electron model for this type of system.