11 research outputs found
Unified Homogenization Theory for Magnetoinductive and Electromagnetic Waves in Split Ring Metamaterials
A unified homogenization procedure for split ring metamaterials taking into
account time and spatial dispersion is introduced. The procedure is based on
two coupled systems of equations. The first one comes from an approximation of
the metamaterial as a cubic arrangement of coupled LC circuits, giving the
relation between currents and local magnetic field. The second equation comes
from macroscopic Maxwell equations, and gives the relation between the
macroscopic magnetic field and the average magnetization of the metamaterial.
It is shown that electromagnetic and magnetoinductive waves propagating in the
metamaterial are obtained from this analysis. Therefore, the proposed time and
spatially dispersive permeability accounts for the characterization of the
complete spectrum of waves of the metamaterial. Finally, it is shown that the
proposed theory is in good quantitative and qualitative agreement with full
wave simulations.Comment: 4 pages, 3 figure
The HITRAN2020 molecular spectroscopic database
The HITRAN database is a compilation of molecular spectroscopic parameters. It was established in the early 1970s and is used by various computer codes to predict and simulate the transmission and emission of light in gaseous media (with an emphasis on terrestrial and planetary atmospheres). The HITRAN compilation is composed of five major components: the line-by-line spectroscopic parameters required for high-resolution radiative-transfer codes, experimental infrared absorption cross-sections (for molecules where it is not yet feasible for representation in a line-by-line form), collision-induced absorption data, aerosol indices of refraction, and general tables (including partition sums) that apply globally to the data. This paper describes the contents of the 2020 quadrennial edition of HITRAN. The HITRAN2020 edition takes advantage of recent experimental and theoretical data that were meticulously validated, in particular, against laboratory and atmospheric spectra. The new edition replaces the previous HITRAN edition of 2016 (including its updates during the intervening years). All five components of HITRAN have undergone major updates. In particular, the extent of the updates in the HITRAN2020 edition range from updating a few lines of specific molecules to complete replacements of the lists, and also the introduction of additional isotopologues and new (to HITRAN) molecules: SO, CH3F, GeH4, CS2, CH3I and NF3. Many new vibrational bands were added, extending the spectral coverage and completeness of the line lists. Also, the accuracy of the parameters for major atmospheric absorbers has been increased substantially, often featuring sub-percent uncertainties. Broadening parameters associated with the ambient pressure of water vapor were introduced to HITRAN for the first time and are now available for several molecules. The HITRAN2020 edition continues to take advantage of the relational structure and efficient interface available at www.hitran.org and the HITRAN Application Programming Interface (HAPI). The functionality of both tools has been extended for the new edition
Molecular dynamics simulation of poly(3-hexylthiophene) helical structure in vacuo and in amorphous polymer surrounding
The stability of poly(3-hexylthiophene) (P3HT) helical structure has been investigated in vacuo and in amorphous polymer surrounding via molecular dynamics-based simulations at temperatures below and above the P3HT melting point. The results show that the helical chain remains stable at room temperature both in vacuo and in amorphous surrounding, and promptly loses its structure at elevated temperatures. However, the amorphous surrounding inhibits the destruction of the helix at higher temperatures. In addition, it is shown that the electrostatic interactions do not significantly affect the stability of the helical structur
The HITRAN 2012 Molecular Spectroscopic Database
This paper describes the status of the latest edition of the HITRAN molecular spectroscopic
compilation. The new edition is meant to replace the previous HITRAN edition of 2008 and its
updates during the intervening years. The HITRAN molecular absorption compilation is
comprised of six major components structured into folders that are freely accessible on the
internet. These folders consist of the traditional line-by-line spectroscopic parameters required
for high-resolution radiative-transfer codes, infrared absorption cross-sections for molecules not
yet amenable to representation in a line-by-line form, ultraviolet spectroscopic parameters,
aerosol indices of refraction, collision-induced absorption data, and general tables such as
partition sums that apply globally to the data. The new HITRAN is greatly extended in terms of
accuracy, spectral coverage, additional absorption phenomena, and validity. Molecules and
isotopologues have been added that address the issues of atmospheres beyond the Earth. Also
discussed is a new initiative that casts HITRAN into a relational database format that offers
many advantages over the long-standing sequential text-based structure that has existed since the
initial release of HITRAN in the early 1970s