Electron-phonon dynamics in an ensemble of nearly isolated nanoparticles

In the spirit of some earlier work on the construction of vector coherent states over matrix domains, we compute here such states associated to some physical Hamiltonians. In particular, we construct vector coherent states of the Gazeau-Klauder type. As a related problem, we also suggest a way to handle degeneracies in the Hamiltonian for building coherent states. Specific physical Hamiltonians studied include a single photon mode interacting with a pair of fermions, a Hamiltonian involving a single boson and a single fermion, a charged particle in a three dimensional harmonic force field and the case of a two-dimensional electron placed in a constant magnetic field, orthogonal to the plane which contains the electron. In this last example, an interesting modular structure emerges for two underlying von Neumann algebras, related to opposite directions of the magnetic field. This leads to the existence of coherent states built out of KMS states for the system.

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“…(2) There exists a measure dν on R + which solves the moment problem 14) are of unit norm and span the space. Thus the vectors…”

Section: Ii2 the Gazeau-klauder Situationmentioning

confidence: 99%

Some physical appearances of vector coherent states and coherent states related to degenerate Hamiltonians

Ali

Багарелло

2005

Journal of Mathematical Physics

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“…The electronic structure of the RE ions is dominated by electron-electron and spin-orbit interaction within the 4f shell. The effect of the reduced dimensionality on the electronic relaxation and the phonon density of states of semiconductor and insulating nanocrystals has been extensively investigated using both a theoretical and an experimental approach [11,12]. As a consequence, the spontaneous emission probability of optical transitions (luminescence lifetime) from RE ionsdoped nanoparticles may be significantly different from their bulk counterparts.…”

Section: Introductionmentioning

confidence: 99%

Understanding the role of particle size on photophysical properties of CdS:Eu3+ nanocrystals

Sadhu

Chowdhury

Patra

2007

Journal of Luminescence

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“…Therefore, excitonic transition in the host material and an improvement in the luminescence intensity is also expected for the semiconductor nanostructures after the rare earths (RE) doping. The effects of the reduced dimensionality on the electronic relaxation and the phonon density-of-states of semiconductor compounds and insulating nanocrystals have been extensively investigated by both theoretical and experimental approaches [7,8]. Doping of II-VI semiconductors compounds with rare earths ions like cerium, terbium and europium, etc., has recently been extensively studied [9].…”

Section: Introductionmentioning

confidence: 99%

Rare earths (Ce, Eu) molar concentration-dependent of the structural and optical properties of CBD-CdS nanofilms

et al. 2018

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It presents the characterization of rare earths (Eu,Ce)-doped CdS nanofilms that were synthesised by the growth technique chemical bath deposition (CBD) at the reservoir temperature of 70 ± 2• C. The doping of CdS with rare earths is performed by varying the synthesis time from 60 to 135 min. The rare earths molar concentration was range from 0.0 ≤ x ≤ 3.5, which was determined by energy dispersive X-ray spectroscopy. X-ray diffraction (XRD) analysis and Raman scattering reveal that CdS nanofilms showed the zinc blende (ZB) crystalline phase. The CdS average nanocrystal size was ranged from 1.84 to 2.67 nm that was determined by the Debye-Scherrer equation from ZB (111) direction, which was confirmed by transmission electron microscopy. Raman scattering shows that the lattice dynamics is characteristic of bimodal behaviour and the multipeaks adjust of the first optical longitudinal mode for the (Eu,Ce)-doped CdS, which denotes the Raman shift of the characteristic peak about 305 cm −1 of the CdS nanocrystals. The CdS nanofilms exhibit a direct bandgap that slightly decreases with increasing doping, from 2.50 to 2.42 eV, which was obtained by room temperature transmittance. The room-temperature photoluminescence of CdS shows the band-to-band transition at 2.88 eV, which is associated to quantum confinement and a dominant radiative band at 2.37 eV that is called the optical signature of interstitial oxygen. The Eu 3+ -doped CdS photoluminescence shows the dominant radiative band at 2.15 eV, which is associated to the intra-4f radiative transition of Eu 3+ ions that corresponds to the magnetic dipole transition, ( 5 D0→ 7 F 1 ).For the Ce 3+ -doped CdS the dominant radiative transition, at 2.06 eV, is clearly redshifted, although the passivation of the CdS nanofilms byCe was approximately by a factor about 21 for the best results.Keywords: CdS; Chemical bath deposition; Rare earths; cerium; europium.Se presenta la caracterización de las nanopelículas de CdS impurificadas con tierras raras (Eu,Ce) que se sintetizaron mediante la técnica de crecimiento deposición de baño químico (CBD) a la temperatura del reservorio de 70 ± 2 • C. La impurificación de CdS con tierras raras se realizó variando el tiempo de síntesis de 60 a 135 min. La concentración molar de las tierras raras fue de 0.0 ≤ x ≤ 3.5, que se determinó mediante espectroscopia de rayos X de energía dispersiva. El análisis de difracción de rayos X (XRD) y dispersión de Raman revelan que las nanopelículas de CdS mostraron la fase cristalina de zinc blenda (ZB). El tamaño medio de los nanocristales de CdS varió de 1.84 a 2.67 nm, que se determinó mediante la ecuación de Debye-Scherrer a partir de la dirección ZB (111), que se confirmó mediante microscopía electrónica de transmisión. La dispersión Raman muestra que la dinámica de la red es característica del comportamiento bimodal y el ajuste multipicos del primer modo longitudinalóptico para el CdS impurificado con (Eu, Ce), el cual denota el desplazamiento Raman del pico característico en aproximadamente 305 ...

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Electron-phonon dynamics in an ensemble of nearly isolated nanoparticles

Cited by 24 publications

References 9 publications

Some physical appearances of vector coherent states and coherent states related to degenerate Hamiltonians

Some physical appearances of vector coherent states and coherent states related to degenerate Hamiltonians

Understanding the role of particle size on photophysical properties of CdS:Eu3+ nanocrystals

Rare earths (Ce, Eu) molar concentration-dependent of the structural and optical properties of CBD-CdS nanofilms

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