Calculation of optical constants of a weak absorption band by the Kramers-Kronig relation

1973 ◽  
Vol 19 (5) ◽  
pp. 1524-1526 ◽  
Author(s):  
V. I. Vettegren' ◽  
A. E. Chmel'
Keyword(s):  
Absorption Band ◽  
Optical Constants ◽  
Weak Absorption ◽  
Weak Absorption Band ◽  
Kronig Relation

Estimation of the infrared absorption of ZnCl2–KBr glass by molecular dynamics

1987 ◽  
Vol 2 (3) ◽  
pp. 357-360 ◽  
Author(s):  
Satoru Inoue ◽  
Mitsuru Tamaki ◽  
Hiroshi Kawazoe ◽  
Masayuki Yamane
Keyword(s):  
Molecular Dynamics ◽  
Absorption Band ◽  
Molecular Dynamic ◽  
Infrared Absorption ◽  
Experimental Results ◽  
Ir Absorption ◽  
Weak Absorption ◽  
Weak Absorption Band ◽  
Oxygen Impurities ◽  
Free Glass

Molecular dynamic calculations have been made on glasses in the ZnCl2–KBr system in order to estimate the infrared (IR) absorption of these glasses. Oxygen-free glass was estimated to be transparent up to 25 μm. Glasses containing oxygen impurities were estimated to be transparent only up to 16 μm, with a weak absorption band around 10.4 μm. This agrees with experimental results of glasses in the ZnCl2–KBr–PbBr2 system.

scholarly journals Rotatory dispersion in the amine series III-The absorption spectra of diamines

1937 ◽  
Vol 162 (909) ◽  
pp. 228-232 ◽  
Keyword(s):  
Nitrogen Atom ◽  
Absorption Band ◽  
Absorption Spectra ◽  
Amino Nitrogen ◽  
Lone Pair ◽  
Optically Active ◽  
Ethylene Diamine ◽  
Weak Absorption ◽  
Weak Absorption Band ◽  
Striking Effect

In view of the striking effect on the rotatory powers of optically active amines which occur when the lone-pair of electrons on the amino-nitrogen atom is saturated, as described in the two preceding papers, it was of importance to investigate the corresponding changes which are indicated in the absorption spectra the corresponding changes which are indicated in the absorption spectra of simple amino compounds. Absorption spectra are therefore now recorded for hydrazine and for ethylene-diamine, and the effect on these spectra of varying the acid concentration of the solutions has been measured. No previous measurements of the absorption of hydrazine in solution have been recorded, but sunao and Imanishi (1931) observed a series of bands between 2400 and 2200 A in the vapour. Ethylene-diamine has been examined by Bielecki and Henri (1913), and Castille and Ruppol (1928) have investigated its hydrochloride. The latter authors reported a weak absorption band in aqueous solutions of the salt (ϵ max = 0·4 at 2631 A), but this observation is not confirmed by the present results. It may be attributed to the presence of an impurity, since, in the first series band (ϵ max = 2 at 2631 A) was also seen, but after recrystallization of the salt it disappeared completely.

An investigation of X-irradiated KCl:H and NaCl:H

1966 ◽  
Vol 294 (1438) ◽  
pp. 359-375 ◽  
Keyword(s):  
Activation Energy ◽  
Hydrogen Atom ◽  
Absorption Band ◽  
Low Temperatures ◽  
Production Mechanism ◽  
Hydrogen Atoms ◽  
Weak Absorption ◽  
Weak Absorption Band ◽  
X Irradiation ◽  
Optical Bleaching

The e.p.r. spectrum of a new hydrogen atom centre called the U 3 centre has been observed after X-irradiation of KC1 :H crystals at low temperatures and has been assigned to hydrogen atoms in chlorine sites. The centre bleaches thermally at 145 °K with an activation energy of 043 ± 0.03 eV. Optical bleaching experiments indicate that the centre has a weak absorption band peaking at 2-9 eV. The centre cannot be produced by ultraviolet irradiation. A production mechanism involving V k centres is proposed and is discussed in detail. The U 3 centre has also been observed in NaCl:H.

A New Method for Determining the Optical Constants of Highly Transparent Solids

2016 ◽  
Vol 71 (1) ◽  
pp. 70-77 ◽  
Author(s):  
Xingcan Li ◽  
Chengchao Wang ◽  
Junming Zhao ◽  
Linhua Liu
Keyword(s):  
Refractive Index ◽  
Optical Constants ◽  
Absorption Index ◽  
New Method ◽  
Transmission Method ◽  
Combination Technique ◽  
Transparent Substrate ◽  
True Value ◽  
Gradient Based ◽  
Kronig Relation

Highly transparent substrates are of interest for a variety of applications, but it is difficult to measure their optical constants precisely, especially the absorption index in the transparent spectral region. In this paper, a combination technique (DOPTM-EM) using both the double optical pathlength transmission method (DOPTM) and the ellipsometry method (EM) is presented to obtain the optical constants of highly transparent substrates, which overcomes the deficiencies of both the two methods. The EM cannot give accurate result of optical constants when the absorption index is very weak. The DOPTM is suitable to retrieve the weak absorption index; however, two sets of solutions exist for the retrieved refractive index and absorption index, and only one is the true value that needs to be identified. In the DOPTM-EM, the optical constants are measured first by using the EM and set as the initial value in the gradient-based inverse method used in the DOPTM, which ensures only the true optical constants are retrieved. The new method simultaneously obtains the refractive index and the absorption index of highly transparent substrate without relying on the Kramers–Kronig relation. The optical constants of three highly transparent substrates (polycrystalline BaF2, CaF2, and MgF2) were experimentally determined within wavelength range from ultraviolet to infrared regions (0.2–14 µm). The presented method will facilitate the measurement of optical constants for highly transparent materials.

Optical constants of poly(ethylene terephthalate) in the range of 1410-cm−1 IR absorption band

2008 ◽  
Vol 50 (5-6) ◽  
pp. 120-123
Author(s):  
N. I. Stas’kov ◽  
I. V. Ivashkevich
Keyword(s):  
Absorption Band ◽  
Optical Constants ◽  
Ethylene Terephthalate ◽  
Ir Absorption ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene

A Study of Na2O-TiO2-SiO2 Glasses by Infrared Spectroscopy

1974 ◽  
Vol 28 (3) ◽  
pp. 256-259 ◽  
Author(s):  
Murli H. Manghnani ◽  
John R. Ferraro ◽  
L. J. Basile
Keyword(s):  
Infrared Spectroscopy ◽  
Absorption Band ◽  
Infrared Absorption ◽  
Vibrational Frequency ◽  
Silicate Glasses ◽  
Molar Ratio ◽  
Frequency Range ◽  
Weak Absorption ◽  
Infrared Absorption Spectra ◽  
The Relationship

The infrared absorption spectra of six Na2O-TiO2-SiO2 glasses in the frequency range of 1600 to 200 cm−1 are reported. These glasses, having a SiO2/Na2O molar ratio of 1.07 to 3.54, and containing 20 or 25 mole % TiO2, demonstrate two main absorptions at ∼950 cm−1 and at ∼450 cm−1. A weak absorption at ∼790 cm−1 becomes progressively weaker in intensity, and a weak shoulder at 1050 cm−1 appears with increasing Na2O content. The frequency of the absorption band at ∼950 cm−1 is found to decrease markedly and systematically with a decrease in the SiO2/Na2O molar ratio, whereas the frequency of the band at ∼450cm−1 shows a slight increase. The infrared results may be interpreted in terms of a lowering of symmetry occurring for the SiO4 units. The effect of TiO2 content on the relationship between vibrational frequency is discussed. The frequency composition curves for glasses containing 20 and 25 mole % of TiO2 intersect at SiO2/Na2O ratio ∼2. A reversal in the frequency vs SiO2/Na2O ratio relation was also found at SiO2/Na2O ∼2 for the sodium silicate glasses.

Optische Eigenschaften von natürlichen und künstlichen Bleichromateinkristallen

1968 ◽  
Vol 23 (12) ◽  
pp. 2014-2018 ◽  
Author(s):  
Franz Rudolf Kessler ◽  
Parvin Daneschfar
Keyword(s):  
Activation Energy ◽  
Refractive Index ◽  
Absorption Band ◽  
Optical Constants ◽  
Charge Carriers ◽  
Free Charge ◽  
Free Electrons ◽  
Absorption Bands ◽  
Unpolarised Light ◽  
No Absorption

Out of solution artificial PbCrO4-single-crystals, monoclin modification, equal to natural Crocoit have been produced. The optical constants for natural and these artificial crystals have been found to be equal by measurements of reflectivity and transmission with unpolarised light in the range 0.3 — 15 µm perpendicular to the (110) -plain. Between 1 and 8 µm the refractive index is constant (n = 2,1). In this region some absorption bands occur (2.8 µm corresponding to the donator activation energy of 0.44 eV and 6 μm). At 0.45 µm there is another absorption band but no absorption edge, which was expected with respect to the photoconductivity. Above 8 µm the optical constants are determined by the reststrahlen band at 11.3 μm. The absorption of free charge carriers is discussed because leadchromate in the literature is known to be a purely electronical conductor. An influence of the free charge carriers in the tested spectral range could not be recognized. From this fact it is possible to give some estimations about the conductivity mechanism respectively the mobility of the free electrons.

scholarly journals Optical Properties of Alkali Halides in Ultraviolet Spectral Regions

Optics ◽  
2019 ◽  
Vol 1 (1) ◽  
pp. 18-31 ◽  
Author(s):  
Khagendra P. Bhandari
Keyword(s):  
Alkali Halide ◽  
Optical Constants ◽  
Complex Function ◽  
Alkali Halides ◽  
Current Theory ◽  
Dielectric Constants ◽  
The Real ◽  
Band Transition ◽  
Alkali Halide Crystals ◽  
Kronig Relation

The optical reflectance spectra of alkali halide crystals KI and RbI were measured over the energy range of 4.14 to 6.91 eV. Both single crystal and poly-crystal samples were used to accomplish this task. The phase θ ( ω ) was computed using the Kramers-Kronig relation between the real and imaginary parts of the complex function, ln r = ln | r | + i θ ( ω ) . Subsequently, the optical constants n and κ were determined from the Fresnel reflectivity equation. The real and imaginary parts of dielectric constants ε 1 and ε 2 were then calculated using n and κ. The optical absorption spectra of the crystal have also been measured in these spectral regions. The spectra agree reasonably well with the current theory concerning exciton peaks. In addition, a shoulder was found in the spectra similar to those previously seen and associated with the band-to-band transition in the alkali iodides.

Calculation of optical constants for weak absorption coatings on weak absorption substrate

2010 ◽  
Vol 22 (5) ◽  
pp. 1026-1030 ◽  
Author(s):  
尚淑珍 Shang Shuzhen ◽  
路贵民 Lu Guimin ◽  
赵祖欣 Zhao Zuxin
Keyword(s):  
Optical Constants ◽  
Weak Absorption
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