Empirical bond polarizability model for fullerenes

1996 ◽  
Vol 53 (19) ◽  
pp. 13106-13114 ◽  
Author(s):  
S. Guha ◽  
J. Menéndez ◽  
J. B. Page ◽  
G. B. Adams
Keyword(s):  
Bond Polarizability

SPECTROSCOPIC STUDIES OF ALCOHOLS: III. FUNDAMENTAL OH STRETCHING BANDS OF 2,2-DI- AND 2,2,2-TRI-HALOETHANOLS

1964 ◽  
Vol 42 (2) ◽  
pp. 340-346 ◽  
Author(s):  
P. J. Krueger ◽  
H. D. Mettee
Keyword(s):  
Spectroscopic Studies ◽  
Kcal Mole ◽  
Temperature Dependent ◽  
Hydrogen Bond Interaction ◽  
Constrained System ◽  
Trans Conformer ◽  
Bond Polarizability ◽  
Inductive Effects ◽  
Geometrically Constrained ◽  
Bond Polarization

The OH stretching region was examined for the compounds F3CCH2OH, Cl2CHCH2OH, Cl3CCH2OH, and Br3CCH2OH in dilute CCl4 solution. The first two compounds exhibit temperature-dependent band asymmetry which is due to trans–gauche equilibria arising from rotation about the C—O bond, with relatively small populations in the trans forms. Enthalpy differences of 3.3 and 2.4 kcal/mole between the conformers were obtained for these two compounds respectively. Although symmetrical at lower temperatures, the band for Cl3CCH2OH shows the presence of a small amount of the trans conformer at temperatures above 45 °C. These results are discussed in terms of intramolecular OH … X hydrogen bond interaction, inductive effects, non-bonded interactions, O—H bond polarization, C—X bond polarizability, and the size of the halogen atoms in a geometrically constrained system.

scholarly journals C60 Filling Rate in Carbon Peapods: A Nonresonant Raman Spectra Analysis

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Fatima Fergani ◽  
Sidi Abdelmajid Ait Abdelkader ◽  
Hassane Chadli ◽  
Brahim Fakrach ◽  
Abdelhai Rahmani ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Experimental Method ◽  
Raman Spectra ◽  
Double Helix ◽  
Single Walled Carbon Nanotubes ◽  
Filling Rate ◽  
Spectra Analysis ◽  
Single Walled Carbon ◽  
Bond Polarizability ◽  
Walled Carbon Nanotubes

We calculated the nonresonant Raman spectra of C60 peapods to determine the concentration of C60 fullerenes inside single-walled carbon nanotubes. We focus on peapods with large diameters for which C60 molecules can adopt a double helix configuration or a two-molecule layer configuration. Our calculations are performed within the framework of the bond-polarizability model combined with the spectral moment’s method. The changes in the Raman spectra as a function of C60 filling rate and the configuration of C60 molecules inside the nanotubes are identified and discussed. Our calculations support the experimental method proposed by Kuzmany to evaluate the concentration of C60 molecules inside nanotubes.

Bond polarizability anisotropy: Resolution of the sign ambiguity

1987 ◽  
Vol 18 (2) ◽  
pp. 141-143 ◽  
Author(s):  
Robert S. Armstrong ◽  
Manuel J. Aroney ◽  
Robin J. H. Clark
Keyword(s):  
Polarizability Anisotropy ◽  
Bond Polarizability

Study of the Raman spectra of phonons in disordered GaSb/AlSb (001) superlattices

2010 ◽  
Vol 88 (9) ◽  
pp. 645-650 ◽  
Author(s):  
D. Berdekas
Keyword(s):  
Shell Model ◽  
Raman Spectra ◽  
Brillouin Zone ◽  
Dynamical Matrix ◽  
Phonon Spectra ◽  
Bond Polarizability ◽  
Lattice Planes

In the present work, we study the influence of disorder in the Raman spectra of the phonons of (GaSb)n/(AlSb)n (001) superlattices (SLs), for n = 1, 2. Τhe disordered superlattices are approximated with primitive cells that are much larger than the primitive cells of the corresponding perfect SLs. We propose that disorder appears because of deviations from the sequence of the GaSb and AlSb layers, which is imposed by symmetry, or because of intermixing of Ga and Al in the cation lattice planes. The dynamical matrix of each SL is constructed from the combination of the dynamical matrices of the bulk crystalline constituents, which have been calculated at certain points of the Brillouin zone with a ten-parameter valence overlap shell model. Further, we have calculated the Raman spectra of the disordered 1 × 1 and 2 × 2 superlattices grown along the (001) direction, using an eight-parameter bond polarizability model, away from resonance conditions. Our results show that intermixing of Ga and Al cations produce Raman activity that is not present in the phonon spectra of perfect superlattices.

Interface Effects on the Raman Spectra of Si/3C-SiC Superlattices

2000 ◽  
Vol 640 ◽  
Author(s):  
E. F. Bezerra ◽  
A. G. Souza Filho ◽  
J. Mendes Filho ◽  
V. Lemos ◽  
V. N. Freire ◽  
...  
Keyword(s):  
Raman Spectra ◽  
Theoretical Calculations ◽  
Linear Chain ◽  
Dispersion Relations ◽  
Chain Model ◽  
Virtual Crystal Approximation ◽  
Smooth Interface ◽  
Bond Polarizability ◽  
Interface Effects

ABSTRACTTheoretical calculations are performed on the role of smooth interfaces in the Raman spectra of Si/3C-SiC superlattices. The dispersion relations were obtained using a linear chain model with the alloyed interface δ-(3C-SiC)0.5(Si)0.5 described in the virtual crystal approximation. A modified bond-polarizability model was used to calculate the Raman spectra. The main results are the enhancement of the Raman spectra and the appearance of new peaks in between those related to the Si quasi confined and the 3C-SiC-confined modes with increasing number δ?of interfacial monolayers (3C-SiC)0.5(Si)0.5. Some of the smooth interface related Raman peaks have intensity comparable with those of an abrupt Si/3C-SiC superlattice.

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