Lattice Vibrations of V2O5. Determination of TO and LO Frequencies from Infrared Reflection and Transmission

1976 ◽  
Vol 76 (2) ◽  
pp. 707-713 ◽  
Author(s):  
P. Clauws ◽  
J. Vennik
Keyword(s):  
Lattice Vibrations ◽  
Reflection And Transmission ◽  
Infrared Reflection

scholarly journals Characterization and Application of a Grazing Angle Objective for Quantitative Infrared Reflection Microspectroscopy

1995 ◽  
Vol 49 (3) ◽  
pp. 354-360 ◽  
Author(s):  
Stephen V. Pepper
Keyword(s):  
Angular Dependence ◽  
Grazing Angle ◽  
Fresnel Reflection ◽  
Angular Aperture ◽  
Incident Intensity ◽  
Specular Reflectance ◽  
Fresnel Reflection Coefficient ◽  
Infrared Reflection ◽  
Good Agreement

A grazing angle objective on an infrared microspectrometer is studied for quantitative spectroscopy by considering the angular dependence of the incident intensity within the objective's angular aperture. The assumption that there is no angular dependence is tested by comparing the experimental reflectance of Si and KBr surfaces with the reflectance calculated by integrating the Fresnel reflection coefficient over the angular aperture under this assumption. Good agreement was found, indicating that the specular reflectance of surfaces can straightforwardly be quantitatively integrated over the angular aperture without considering nonuniform incident intensity. This quantitative approach is applied to the thickness determination of dipcoated Krytox on gold. The infrared optical constants of both materials are known, allowing the integration to be carried out. The thickness obtained is in fair agreement with the value determined by ellipsometry in the visible. Therefore, this paper illustrates a method for more quantitative use of a grazing angle objective for infrared reflectance microspectroscopy.

scholarly journals WAVE TRANSMISSION THROUGH TRAPEZOIDAL BREAKWATERS

1978 ◽  
Vol 1 (16) ◽  
pp. 129 ◽  
Author(s):  
Ole Secher Madsen ◽  
Paisal Shusang ◽  
Sue Ann Hanson
Keyword(s):  
Energy Dissipation ◽  
Approximate Method ◽  
Cross Section ◽  
Wave Energy ◽  
Graphical Form ◽  
Dissipated Energy ◽  
Simple Method ◽  
Reflection And Transmission ◽  
Transmission Coefficients

In a previous paper Madsen and White (1977) developed an approximate method for the determination of reflection and transmission characteristics of multi-layered, porous rubble-mound breakwaters of trapezoidal cross-section. This approximate method was based on the assumption that the energy dissipation associated with the wave-structure interaction could be considered as two separate mechanisms: (1) an external, frictional dissipation on the seaward slope; (2) an internal dissipation within the porous structure. The external dissipation on the seaward slope was evaluated from the semi-theoretical analysis of energy dissipation on rough, impermeable slopes developed by Madsen and White (1975). The remaining wave energy was represented by an equivalent wave incident on a hydraulically equivalent porous breakwater of rectangular cross-section. The partitioning of the remaining wave energy among reflected, transmitted and internally dissipated energy was evaluated as described by Madsen (1974), leading to a determination of the reflection and transmission coefficients of the structure. The advantage of this previous approximate method was its ease of use. Input data requirements were limited to quantities which would either be known (water depth, wave characteristics, breakwater geometry, and stone sizes) or could be estimated (porosity) by the design engineer. This feature was achieved by the employment of empirical relationships for the parameterization of the external and internal energy dissipation mechanisms. General solutions were presented in graphical form so that calculations could proceed using no more sophisticated equipment than a hand calculator (or a slide rule). This simple method gave estimates of transmission coefficients in excellent agreement with laboratory measurements whereas its ability to predict reflection coefficients left a lot to be desired.

scholarly journals The Orbit?Lattice Interaction for Lanthanide Ions. I. Determination of Empirical Parameters

1978 ◽  
Vol 31 (1) ◽  
pp. 79 ◽  
Author(s):  
DJ Newman
Keyword(s):  
Lanthanide Ions ◽  
Lattice Vibrations ◽  
Superposition Model ◽  
Coupling Parameters ◽  
Paramagnetic Ions ◽  
Theoretical Results

The coupling between lattice vibrations and electrons in the partly filIed shells of paramagnetic ions is normaIIy presumed to take place via a localized complex consisting of the paramagnetic ion surrounded by its ligands. In such cases the number of parameters is reduced significantly by the use of the superposition model. This model, with some related approximations, has been employed to determine coupling parameters for fluorine, chlorine and oxygen ligands using both experimental and theoretical results.

Thin-Film Optical Constants Determined from Infrared Reflectance and Transmittance Measurements

1989 ◽  
Vol 43 (6) ◽  
pp. 1027-1032 ◽  
Author(s):  
Thierry Buffeteau ◽  
Bernard Desbat
Keyword(s):  
Thin Films ◽  
Optical Constants ◽  
Grazing Incidence ◽  
Infrared Region ◽  
Matrix Formalism ◽  
Experimental Conditions ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Multilayered Systems

A general method based upon reflectance and transmittance measurements in the infrared region has been developed for the determination of the optical constants n( v) and k( v) of thin films deposited on any substrate (transparent or not). The corresponding computer program, written in FORTRAN 77, involves three main parts: (1) a matrix formalism to compute reflection and transmission coefficients of multilayered systems; (2) an iterative Newton-Raphson method to estimate the optical constants by comparison of the calculated and experimental values; and (3) a fast Kramers-Krönig transform to improve the accuracy of calculating the refractive index. The first part of this program can be used independently to simulate reflection and transmission spectra of any multilayered system using various experimental conditions. Two practical examples are given for illustration. Simulation of reflection spectra at grazing incidence for thin films deposited on a metal surface and determination of the optical constants for thin CaF2 layers deposited on a silicon substrate are presented.

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