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Carini, Louis

doi:10.2466/pms.1968.26.3.931

Cited by 4 publications

(2 citation statements)

References 8 publications

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“…This seems to imply that the network hardening is sufficient to explain the evolution with y of the RS intensity. Measurements of the specific heat C p [39] of boron oxide and lithium diborate indicate that their excess in C p /T 3 scales with their Debye values C D /T 3 . The latter being proportional to 1/v 3 L , the above result simply implies that the coupling to light of the QLVs does not vary much with y.…”

Section: The Boson Peak Of Lithium Borate Glassesmentioning

confidence: 99%

Nature of the hyper-Raman active vibrations of lithium borate glasses

Hehlen

Vacher

Courtens

2008

J. Phys.: Condens. Matter

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Hyper-Raman spectra of two lithium borate glasses, 4B 2 O 3 :Li 2 O and 2B 2 O 3 :Li 2 O, are compared to those of pure boron oxide glass, v-B 2 O 3 . A mode analysis is performed using a structural model based on the symmetry of the elementary structural units (ESUs) constituting the glasses. Most spectral components arise from internal vibrations of BO 3 triangles, B 3 O 3 boroxol rings, and BO 4 tetrahedra. In particular, a mode associated with stretching motions of BO 4 units can be assigned to a vibration of F 2 symmetry in the T d tetrahedral point group. The hyper-Raman scattering intensity of its transverse optic component appears to be proportional to the number of BO 4 units in the glass. The boson peak observed in hyper-Raman scattering arises from external modes of rigid ESUs which correspond to librational motions coupled to their translations. The scattering strength of these modes strongly decreases with increasing Li concentration. In pure v-B 2 O 3 , external modes of boroxols presumably dominate this scattering. The decrease in the boroxol concentration in lithium borate glasses correlates with the apparent hardening of the boson peak.

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Section: The Boson Peak Of Lithium Borate Glassesmentioning

confidence: 99%

Nature of the hyper-Raman active vibrations of lithium borate glasses

Hehlen

Vacher

Courtens

2008

J. Phys.: Condens. Matter

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“…The e --ph coupling constants α and β are thus obtained as fitting parameters. The Debye temperature (T D = 825.3 K) of YAB has been derived by specific heat measurements on a pure YAB sample in the temperature range 1.5-25 K [13]. Due to the very small separation (∼3.3 cm -1 ) between the sublevels 1 and 2 of the Dy 3+ ground manifold [8], it is difficult to analyse properly the detailed temperature dependence of the Dy 3+ line position and shift.…”

Section: Electron-phonon Interactionmentioning

confidence: 99%

Electron‐phonon interaction in Er and Dy doped YAl₃(BO₃)₄ single crystals

Mazzera

Baraldi

Capelletti

et al. 2007

Phys. Status Solidi (c)

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In the present work high resolution Fourier Transform spectroscopy is applied to monitor the electronphonon (e --ph) interaction in YAB single crystals doped with trivalent Er and Dy ions. The electronphonon coupling is analysed by monitoring the shape, width, and position of the zero-phonon lines induced by Er 3+. The shift and broadening with temperature increasing are discussed in the framework of the two-phonon Raman scattering. The e --ph interaction is revealed even by the presence, in the absorption spectra of Er and Dy doped YAB crystals, of new weak lines attributed to vibronic transitions. The energy separations between the vibronic and the ZP lines are compared with IR-active modes measured on YAB crystals. Boron isotopic effects are also put in evidence. , thus the knowledge of the electron-phonon (e --ph) coupling strength is important not only from a fundamental point of view, but also from an applicative one. Information about the e --ph interaction can be derived from optical absorption spectra from two experimental observations: 1) the temperature induced shift and broadening of the zero phonon (ZP) lines and 2) the presence of new weak lines attributed to vibronic transitions. Different mechanisms can produce the line broadening: non-radiative decay or Raman relaxation of the ion to lower energy states involving one or more phonons, resonant or Raman excitation to higher energy states, and Raman scattering of phonons which maintains the ion in the same electronic state. The first four processes affect the line width by shortening the lifetime, while the last broadens the energy levels without removing the electrons from it. Since the width obtained from the inverse of the decay times is much lower than that measured from the spectra, the two phonon Raman scattering is the main contribution [2]. Thus, the width change ∆E i of the i th line can be written as

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