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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.
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TL;DR: In this article, the degree of coupling between free electron and nitrogen vibrational temperatures in weakly ionized nozzle expansions of shock-heated nitrogen has been determined, and the resultant data were analytically correlated by coupling chemical nonequilibrium with nitrogen vibrations.
Abstract: The degree of coupling between free electron and nitrogen vibrational temperatures in weakly ionized nozzle expansions of shock‐heated nitrogen has been determined. Free electron temperatures were measured with Langmuir probes while nitrogen vibrational temperatures were determined with a new instrument based on the electron beam technique. The resultant data were analytically correlated by coupling chemical nonequilibrium with nitrogen vibrational and free electron temperature nonequilibrium. It was found that a vibrational loss factor of 7 × 10−4 and an effective translational‐rotational loss factor of 4.26 × 10−4 best predicted the measured electron temperature distributions.
46 citations
TL;DR: In this paper, the Hartree-Fock approximation for the core electrons of the target was investigated and it was shown that each core electron can be regarded as stopping the proton independent of all other electrons without restriction.
Abstract: The electronic energy loss of MeV-protons in crystals is investigated in the Hartree-Fock approximation for the core electrons of the target. It turns out that each core electron can be regarded as stopping the proton independent of all other electrons without restriction by the Pauli principle. For the channeling stopping power the impact parameter dependent energy loss of a proton moving rectilinearly past a crystal ion is calculated in first Born approximation. Low excitations of the core electrons lead to a long range impact parameter dependence, whereas high excitations contribute to the energy loss proportional to the electron density sampled along the proton trajectory. The results are applied to 4 MeV proton channeling along the main channels of Si using Clementi wave functions for the core electrons and a free electron approximation for the valence electrons. The comparison with the experimental results of Clarket al. yields good agreement. In the high velocity limit a reduction of the channeling stopping power to 0.64(0.83) of the random value is predicted for Si(C).
46 citations
TL;DR: In this article, the optical constants of liquid germanium, tin and lead have been measured by a reflection method for wave numbers between 4000 and 27 000 cm−1 (wavelengths 2·5 to 0·37 microns).
Abstract: The optical constants of liquid germanium, tin and lead have been measured by a reflection method for wave numbers between 4000 and 27 000 cm−1 (wavelengths 2·5 to 0·37 microns). The temperature variation of the optical constants was measured for tin and lead. The experimental results follow approximately the Drude free electron formulae if the number of free electrons per atom, N o and their relaxation time, τ, are treated as adjustable parameters. The values of N o lie between 4·3 and 4·7, with a slight temperature variation. The values of the static conductivity calculated from N o and τ are compared with electrically measured values. Previous optical measurements on evaporated films of tin and lead have indicated values of N o between 1·2 and 1·4 for the solid metals.
46 citations
TL;DR: In this article, a new relativistic description of quantum electrodynamics is presented, which is based on the Klein-Gordon equation, reformulated to consider spin effects, and the properties of free electron and photon states related to this wave equation are investigated.
46 citations
TL;DR: In this article, the resistivity, Hall coefficient and absolute thermoelectric power of the liquid Hg-In alloy system are reported and discussed in relation to the free electron theory of liquid metal properties.
Abstract: Measurements of the resistivity, Hall coefficient and absolute thermoelectric power of the liquid Hg–In alloy system are reported and discussed in relation to the free electron theory of liquid metal properties. The Hall coefficient does not have the ‘free electron’ value. The thermoelectric power has a maximum at about 3 at. % In which is contrary to expectations and at present unexplained.
46 citations