scholarly journals Refractive Indices of Ge and Si at Temperatures between 4–296 K in the 4–8 THz Region

2021 ◽  
Vol 11 (2) ◽  
pp. 487
Author(s):  
Mira Naftaly ◽  
Steve Chick ◽  
Guy Matmon ◽  
Ben Murdin
Keyword(s):  
Refractive Index ◽  
Fourier Transform ◽  
Temperature Dependence ◽  
Phenomenological Model ◽  
Transmission Mode ◽  
High Resistivity ◽  
Refractive Indices ◽  
Fourier Transform Spectrometer ◽  
Mode A

Refractive indices of high resistivity Si and Ge were measured at temperatures between 4–296 K and at frequencies between 4.2–7.7 THz using a Fourier-transform spectrometer (FTS) in transmission mode. A phenomenological model of the temperature dependence of the refractive index is proposed.

Collision-induced absorption in ethane–rare gas mixtures

1983 ◽  
Vol 61 (4) ◽  
pp. 633-640 ◽  
Author(s):  
I. R. Dagg ◽  
L. A. A. Read ◽  
A. Anderson
Keyword(s):  
Fourier Transform ◽  
Temperature Dependence ◽  
Quadrupole Moment ◽  
Gas Mixtures ◽  
Rare Gas ◽  
Fourier Transform Spectrometer ◽  
Rare Gases ◽  
Induced Absorption ◽  
Absolute Value ◽  
The Absolute

The collision-induced spectra of mixtures of ethane and each of the rare gases He, Ar, Kr, and Xe in the 40–360 cm−1 region have been obtained using a Michelson Fourier transform spectrometer. In addition, the temperature dependence of the absorption in ethane and ethane–xenon mixtures is reported. All results have been analyzed according to the theory for quadrupole induced rotation–translation absorption. The absolute value of the quadrupole moment of ethane is estimated to be less than 1.0 B and most likely less than 0.5 B. Various speculations are made concerning the induction mechanisms (other than quadrupolar) for each of the mixtures.

scholarly journals On the Pressure and Temperature Dependence of the Absorption Coefficient of NH3

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
F. Aousgi ◽  
S. Hadded ◽  
H. Aroui
Keyword(s):  
Fourier Transform ◽  
High Resolution ◽  
Absorption Coefficient ◽  
Temperature Dependence ◽  
Quadratic Function ◽  
Fourier Transform Spectrometer ◽  
Absorption Coefficients ◽  
Linear Evolution ◽  
Exponential Law ◽  
Quantum Numbers

The effects of pressure and temperature on the absorption coefficient of ammonia (NH3) gas self-perturbed and perturbed by nitrogen (N2) gas have been measured. We varied the gas pressure from 10 to 160 Torr and the temperature from 235 to 296 K in order to study the absorption coefficient at the center and the wings of lines in the ν4 band of NH3. These measurements were made using a high resolution (0.0038 cm-1) Bruker Fourier-transform spectrometer. These spectra have been analyzed using the method of multipressure technique permitting to succeed to an evolution of the absorption coefficient with the pressure and the quantum numbers J and K of the NH3 molecule. The results show that the absorption coefficient varies as a quadratic function of the pressure at the center of a given line. However, it has a linear evolution in the wings of the line. Moreover, the absorption coefficients are inversely proportional to temperature in the wings when NH3 lines are broadened by N2. The retrieved values of these coefficients were used to derive the temperature dependence of N2 broadening NH3 lines. The absorption coefficients were shown to fit closely the well-known exponential law.

Solvent induced frequency shifts of the C—H stretching bands of n-octane. A Fourier transform infrared study

1981 ◽  
Vol 59 (9) ◽  
pp. 1357-1360 ◽  
Author(s):  
D. G. Cameron ◽  
S. C. Hsi ◽  
J. Umemura ◽  
H. H. Mantsch
Keyword(s):  
Fourier Transform ◽  
Gas Phase ◽  
Carbon Disulfide ◽  
Fourier Transform Infrared ◽  
Dielectric Constants ◽  
Refractive Indices ◽  
Fourier Transform Spectrometer ◽  
Infrared Study ◽  
Frequency Shifts ◽  
Frequency Behavior

Using a Fourier transform spectrometer the frequencies and bandwidths of the infrared active C—H stretching modes of n-octane were determined in a variety of solvents with refractive indices from 1.63 (carbon disulfide) to 1.28 (n-perfluorooctane), and dielectric constants from 37.5 (acetonitrile) to 1.8 (n-perfluorooctane). The frequency shifts were correlated with the refractive indices and dielectric constants of the solvents, and fitted with the equation of David and Hallam (Spectrochim. Acta, Part A, 23, 593 (1967)). Generally, solution results in shifts to frequencies lower than those observed in the gas phase. However, solution in n-perfluorooctane resulted in a shift to a higher frequency, behavior in accord with the above equation but not previously observed.

Light microscopy of ceramics

1993 ◽  
Vol 51 ◽  
pp. 908-909
Author(s):  
Walter C. McCrone
Keyword(s):  
Refractive Index ◽  
Light Microscopy ◽  
Light Microscope ◽  
Polarized Light ◽  
Refractive Indices ◽  
Complete Coverage ◽  
The Subject ◽  
Lower Refractive Index

An excellent chapter on this subject by V.D. Fréchette appeared in a book edited by L.L. Hench and R.W. Gould in 1971 (1). That chapter with the references cited there provides a very complete coverage of the subject. I will add a more complete coverage of an important polarized light microscope (PLM) technique developed more recently (2). Dispersion staining is based on refractive index and its variation with wavelength (dispersion of index). A particle of, say almandite, a garnet, has refractive indices of nF = 1.789 nm, nD = 1.780 nm and nC = 1.775 nm. A Cargille refractive index liquid having nD = 1.780 nm will have nF = 1.810 and nC = 1.768 nm. Almandite grains will disappear in that liquid when observed with a beam of 589 nm light (D-line), but it will have a lower refractive index than that liquid with 486 nm light (F-line), and a higher index than that liquid with 656 nm light (C-line).

Application of the turbidity ratio method in the spherical particle size determination in the range m ∈ and α ∈

1979 ◽  
Vol 44 (7) ◽  
pp. 2064-2078 ◽  
Author(s):  
Blahoslav Sedláček ◽  
Břetislav Verner ◽  
Miroslav Bárta ◽  
Karel Zimmermann
Keyword(s):  
Refractive Index ◽  
Spherical Particle ◽  
Ratio Method ◽  
Refractive Indices ◽  
Relative Refractive Index ◽  
Particle Size Determination ◽  
The Individual ◽  
The Given ◽  
Turbidity Ratio ◽  
Selection Of

Basic scattering functions were used in a novel calculation of the turbidity ratios for particles having the relative refractive index m = 1.001, 1.005 (0.005) 1.315 and the size α = 0.05 (0.05) 6.00 (0.10) 15.00 (0.50) 70.00 (1.00) 100, where α = πL/λ, L is the diameter of the spherical particle, λ = Λ/μ1 is the wavelength of light in a medium with the refractive index μ1 and Λ is the wavelength of light in vacuo. The data are tabulated for the wavelength λ = 546.1/μw = 409.357 nm, where μw is the refractive index of water. A procedure has been suggested how to extend the applicability of Tables to various refractive indices of the medium and to various turbidity ratios τa/τb obtained with the individual pairs of wavelengths λa and λb. The selection of these pairs is bound to the sequence condition λa = λ0χa and λb = λ0χb, in which b-a = δ = 1, 2, 3; a = -2, -1, 0, 1, 2, ..., b = a + δ = -1, 0, 1, 2, ...; λ0 = λa=0 = 326.675 nm; χ = 546.1 : 435.8 = 1.2531 is the quotient of the given sequence.

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