Calculating van der Waals-London dispersion spectra and Hamaker coefficients of carbon nanotubes in water from ab initio optical properties

2007 ◽  
Vol 101 (5) ◽  
pp. 054303 ◽  
Author(s):  
R. F. Rajter ◽  
R. H. French ◽  
W. Y. Ching ◽  
W. C. Carter ◽  
Y. M. Chiang
Keyword(s):  
Carbon Nanotubes ◽  
Optical Properties ◽  
Ab Initio ◽  
Van Der Waals ◽  
London Dispersion

scholarly journals Optical Properties and van der Waals-London Dispersion Interactions in Inorganic and Biomolecular Assemblies

2014 ◽  
Vol 1619 ◽  
Author(s):  
Daniel M. Dryden ◽  
Yingfang Ma ◽  
Jacob Schimelman ◽  
Diana Acosta ◽  
Lijia Liu ◽  
...  
Keyword(s):  
Optical Properties ◽  
Spectroscopic Ellipsometry ◽  
Density Functional ◽  
Type I Collagen ◽  
Strong Dependence ◽  
Van Der Waals ◽  
Fundamental Absorption Edge ◽  
Type I ◽  
Dispersion Interactions ◽  
London Dispersion

ABSTRACTThe optical properties and electronic structure of AlPO4, SiO2, Type I collagen, and DNA were examined to gain insight into the van der Waals-London dispersion behavior of these materials. Interband optical properties of AlPO4 and SiO2 were derived from vacuum ultraviolet spectroscopy and spectroscopic ellipsometry, and showed a strong dependence on the crystals’ constituent tetrahedral units, with strong implications for the role of phosphate groups in biological materials. The UV-Vis decadic molar absorption of four DNA oligonucleotides was measured, and showed a strong dependence on composition and stacking sequence. A film of Type I collagen was studied using spectroscopic ellipsometry, and showed a characteristic shoulder in the fundamental absorption edge at 6.05 eV. Ab initio calculations based on density functional theory corroborated the experimental results and provided further insights into the electronic structures, interband transitions and vdW-Ld interaction potentials for these materials.

scholarly journals Optical Properties and van der Waals - London Dispersion Interactions of Polystyrene Determined by Vacuum Ultraviolet Spectroscopy and Spectroscopic Ellipsometry

2007 ◽  
Vol 60 (4) ◽  
pp. 251 ◽  
Author(s):  
Roger H. French ◽  
Karen I. Winey ◽  
Min K. Yang ◽  
Weiming Qiu
Keyword(s):  
Free Energy ◽  
Optical Properties ◽  
Surface Free Energy ◽  
Vacuum Ultraviolet ◽  
Van Der Waals ◽  
Interband Transitions ◽  
Dispersion Interactions ◽  
Dispersion Component ◽  
London Dispersion ◽  
Hamaker Constants

The interband optical properties of polystyrene in the vacuum ultraviolet (VUV) region have been investigated using combined spectroscopic ellipsometry and VUV spectroscopy. Over the range 1.5–32 eV, the optical properties exhibit electronic transitions we assign to three groupings, E1, E2, and E3, corresponding to a hierarchy of interband transitions of aromatic (π → π*), non-bonding (n → π*, n → σ*), and saturated (σ → σ*) orbitals. In polystyrene there are strong features in the interband transitions arising from the side-chain π bonding of the aromatic ring consisting of a shoulder at 5.8 eV (E1′) and a peak at 6.3 eV (E1), and from the σ bonding of the C–C backbone at 12 eV (E3′) and 17.1 eV (E3). These E3 transitions have characteristic critical point line shapes associated with one-dimensionally delocalized electron states in the polymer backbone. A small shoulder at 9.9 eV (E2) is associated with excitations possibly from residual monomer or impurities. Knowledge of the valence electronic excitations of a material provides the necessary optical properties to calculate the van der Waals–London dispersion interactions using Lifshitz quantum electrodynamics theory and full spectral optical properties. Hamaker constants and the van der Waals–London dispersion component of the surface free energy for polystyrene were determined. These Lifshitz results were compared to the total surface free energy of polystyrene, polarity, and dispersive component of the surface free energy as determined from contact angle measurements with two liquids, and with literature values. The Lifshitz approach, using full spectral Hamaker constants, is a more direct determination of the van der Waals–London dispersion component of the surface free energy of polystyrene than other methods.

scholarly journals Spectral mixing formulations for van der Waals–London dispersion interactions between multicomponent carbon nanotubes

2008 ◽  
Vol 104 (5) ◽  
pp. 053513 ◽  
Author(s):  
Rick Rajter ◽  
Roger H. French ◽  
Rudi Podgornik ◽  
W. Y. Ching ◽  
V. Adrian Parsegian
Keyword(s):  
Carbon Nanotubes ◽  
Van Der Waals ◽  
Dispersion Interactions ◽  
London Dispersion ◽  
Spectral Mixing
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