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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 paper, the Coulombic wave functions rather than plane waves for the free electron states were used to increase the calculated rate of capture of electrons by a factor of about 200 at liquid helium temperatures.
Abstract: The use of Coulombic wave functions rather than plane waves for the free electron states is found to increase the calculated rate of capture of electrons by a factor of about 200 at liquid helium temperatures. Results calculated for shallow traps in Ge and Si are now found to be consistent with the upper limit set on the photoconductive lifetime by the experiment of Burstein, Overly, and Davisson. The Born-Oppenheimer and Hartree approximations used in our calculations were found to yield identical results at low temperatures in these materials.
41 citations
TL;DR: In this article, the stability of metallic thin films is studied with a free electron model, which is popularly known as the model of ''particle in a box.'' A detailed theoretical framework is presented, along with discussion on typical metals, such as Pb, Al, Ag, Na, and Be.
Abstract: The stability of metallic thin films is studied with a free electron model, which is popularly known as the model of ``particle in a box.'' A detailed theoretical framework is presented, along with discussion on typical metals, such as Pb, Al, Ag, Na, and Be. This simple model is found to be able to describe well the oscillation pattern of stability for continuous metallic films. In particular, it yields even-odd oscillations in the stability of Pb(111) film, consistent with both experimental observation and ab initio results. However, the free electron model is too crude to predict at what thickness a film is stable. Film stability is further examined with a model of ``particle in a corrugated box,'' where a lattice potential is added along the vertical direction of a film. The effect of lattice potential is found not substantial.
41 citations
TL;DR: In this paper, semi-empirical intermediate-neglect-of-differential-overlap (INDO) calculations for free electron polarons, single-triplet excitons and the excitonic phase in BaTiO3 perovskite crystal are presented.
Abstract: As an extension of our previous study on the electron polarons and excitons in KNbO3 and KTaO3 [1, 2], we present here results of semiempirical intermediate-neglect-of-differential-overlap (INDO) calculations for free electron polarons, single-triplet excitons and the excitonic phase in BaTiO3 perovskite crystal. Our INDO calculations confirm the existence of self-trapped electrons in BaTiO3. The corresponding lattice relaxation energy is 0.24 eV and the optical absorption energy 0.69 eV. An electron in the ground state occupies the t2g orbital of the Ti 3+ ion. Its orbital degeneracy is lifted by a combination of the breathing and Jahn–Teller modes when four nearest equatorial O atoms are displaced by 1.53% a0 outwards in the x–y plane and another two nearest oxygens shift 1.1% inwards, along the z-axis. Our INDO calculations show that creation of charge-transfer vibronic exciton (CTVE) in BaTiO3 crystal is accompanied by a strong lattice distortion; the relevant energy gain due to CTVE formation is 2.2 eV. Moreover, our INDO calculations predict the existence of a new crystalline phase—that of CTVEs in BaTiO3 where strongly correlated CTVEs are located in each unit cell of a crystal. (Some figures in this article are in colour only in the electronic version)
40 citations
TL;DR: In this paper, the first ultrafast temporally, spectrally, and angularly resolved x-ray scattering measurements from shock-compressed matter were presented, where the experimental spectra yield the absolute elastic and inelastic scattering intensities from the measured density of free electrons.
Abstract: We present the first ultrafast temporally, spectrally, and angularly resolved x-ray scattering measurements from shock-compressed matter. The experimental spectra yield the absolute elastic and inelastic scattering intensities from the measured density of free electrons. Laser-compressed lithium-hydride samples are well characterized by inelastic Compton and plasmon scattering of a K-alpha x-ray probe providing independent measurements of temperature and density. The data show excellent agreement with the total intensity and structure when using the two-species form factor and accounting for the screening of ion-ion interactions.
40 citations
TL;DR: These results link the geometry of adlayer molecules with localization of excess electrons at interfaces with evidence for electron localization in 2D at metal-dielectric interfaces is reported.
Abstract: Evidence for electron localization in 2D at metal-dielectric interfaces is reported. A nondispersive peak, derived from the image-potential state and observed in angle-resolved two-photon photoemission, is assigned to localized excess electrons. The image electron on alkane monolayers is a free electron. Bilayers of chain or ring alkanes show both localized and delocalized states; electrons are localized on trilayer n-pentane. Bilayers and trilayers of neopentane show no localization. Our results link the geometry of adlayer molecules with localization of excess electrons at interfaces.
40 citations