scholarly journals Pressure-induced infrared absorption of the fundamental band of hydrogen in H2–Ne and H2–Kr mixtures at room temperature

1968 ◽  
Vol 46 (12) ◽  
pp. 1373-1379 ◽  
Author(s):  
S. Paddi Reddy ◽  
W. F. Lee
Keyword(s):  
Infrared Absorption ◽  
Path Length ◽  
Room Temperature ◽  
Absorption Coefficients ◽  
Fundamental Band ◽  
Low Pressures

The pressure-induced infrared absorption of the fundamental band of hydrogen in H2–Ne and H2–Kr mixtures was studied at room temperature at a path length of 25.8 cm at pressures up to 400 atmospheres for different base pressures of hydrogen. In the enhancement absorption profiles of the band in H2–Ne mixtures, the S(1) line at all pressures and the QP component at low pressures show doublet structures. In the enhancement contours in H2–Kr mixtures, there is an indication of the QQ component between the QP and QR maxima at higher pressures, and the O and S lines are much stronger than the corresponding lines in H2–Ne mixtures. Integrated absorption coefficients were measured for each of the mixtures studied, and the binary and ternary absorption coefficients were derived. The values of the binary coefficients are 2.37 × 10−35 cm6 s−1 for H2–Ne and 7.56 × 10−35 cm6 s−1 for H2–Kr.

Further studies on the collision-induced absorption of the fundamental band of hydrogen at room temperature

1969 ◽  
Vol 47 (24) ◽  
pp. 2745-2751 ◽  
Author(s):  
G. Varghese ◽  
S. Paddi Reddy
Keyword(s):  
Binary Mixture ◽  
Infrared Absorption ◽  
Path Length ◽  
Room Temperature ◽  
Absorption Coefficients ◽  
Fundamental Band ◽  
Induced Absorption ◽  
Two Peaks

The collision-induced infrared absorption of the fundamental band of hydrogen in H2–O2 and H2–Xe mixtures was studied at room temperature at a path length of 105.2 cm at pressures up to 250 atm for different base pressures of hydrogen. The enhancement absorption profiles of the band in H2–O2 mixtures show the usual features of collision-induced absorption. However, the enhancement profiles in H2–Xe mixtures show some interesting new features. These are: the separation between the peaks of the two components of the Q branch remains almost constant with increasing density of the mixture; at all densities, the intensities of these two peaks are almost equal; and the lines of the quadrupolar branches O and S are more pronounced than those in any other binary mixture of hydrogen studied previously. Integrated absorption coefficients were measured for each of the mixtures and the binary and ternary absorption coefficients were derived. The values of the binary coefficients are 6.12 × 10−35 cm6 s−1 for H2–O2, and 11.34 × 10−35 cm6 s−1 for H2–Xe. The ternary coefficient is zero for H2–O2, whereas it has a large negative value for H2–Xe.

INFRARED ABSORPTION OF DEUTERIUM INDUCED BY INTERMOLECULAR FORCES

1965 ◽  
Vol 43 (5) ◽  
pp. 793-799 ◽  
Author(s):  
S. Paddi Reddy ◽  
C. W. Cho
Keyword(s):  
Absorption Band ◽  
Absorption Coefficient ◽  
Infrared Absorption ◽  
Room Temperature ◽  
Intermolecular Forces ◽  
Absorption Coefficients ◽  
Fundamental Band ◽  
Molecular Parameters ◽  
The Individual ◽  
Gas Pressures

The pressure-induced fundamental infrared absorption band of deuterium has been investigated in the pure gas for gas pressures up to 250 atm at room temperature. The binary and ternary absorption coefficients were determined from the integrated absorption coefficients of the fundamental band at different densities of the gas. The splitting of the Q branch into two well-resolved components QP and QR was observed; the contours also exhibit pronounced S(0) and S(2) components with an indication of the S(1) and O(2) components. The existing theory and the available molecular parameters of deuterium were used to calculate the binary absorption coefficients of the individual lines of the O and S branches and of the quadrupole part of the Q branch. From these calculations and the experimental value of the total binary absorption coefficient of the fundamental band, the overlap part of the binary absorption coefficient of the Q branch was estimated.

Interference effects in the spectrum of HD: IV: the pure rotational band at room temperature

1986 ◽  
Vol 64 (3) ◽  
pp. 227-231 ◽  
Author(s):  
A. R. W. McKellar
Keyword(s):  
Spectral Resolution ◽  
Rotational Band ◽  
Path Length ◽  
Room Temperature ◽  
Dipole Transition ◽  
Rotational Spectrum ◽  
Density Range ◽  
Interference Effects ◽  
Fundamental Band ◽  
Line Strengths

The rotational spectrum of HD has been studied in absorption at room temperature for a density range of 6–57 amagat. Spectra were obtained in the 170- to 360-cm−1 region, including the R0(1), R0(2), and R0(3) transitions, with a 1-m path length and a spectral resolution varying from 0.05 to 0.20 cm−1. The observed line strengths were used to determine values for the dipole transition moments of HD in the range of 7.4 to 7.8 × 10−4 D, which is somewhat lower than currently accepted theoretical values of about 8.3–8.4 × 10−4 D. Only very small effects (≈0.2% per amagat) were found due to collisional interference on the line strengths; this result contrasts with much larger interference effects observed in the fundamental band, and it also casts some doubt on other recent studies of the rotational spectrum where larger interference effects were reported.

scholarly journals Infrared Absorption and Its Sources of CdZnTe at Cryogenic Temperature

2022 ◽  
Author(s):  
Hiroshi Maeshima ◽  
Kosei Matsumoto ◽  
Yasuhiro Hirahara ◽  
Takao Nakagawa ◽  
Ryoichi Koga ◽  
...  
Keyword(s):  
Absorption Coefficient ◽  
Infrared Absorption ◽  
Cryogenic Temperature ◽  
Room Temperature ◽  
Wavelength Region ◽  
Room Temperature Resistivity ◽  
Absorption Model ◽  
Acceptor Level ◽  
Absorption Coefficients ◽  
Temperature Resistivity

AbstractTo reveal the causes of infrared absorption in the wavelength region between electronic and lattice absorptions, we measured the temperature dependence of the absorption coefficient of p-type low-resistivity ($$\sim 10^2~ \Omega \mathrm{cm}$$ ∼ 10 2 Ω cm ) CdZnTe crystals. We measured the absorption coefficients of CdZnTe crystals in four wavelength bands ($$\lambda =6.45$$ λ = 6.45 , 10.6, 11.6, 15.1$$~\mu $$ μ m) over the temperature range of $$T=8.6$$ T = 8.6 -300 K with an originally developed system. The CdZnTe absorption coefficient was measured to be $$\alpha =0.3$$ α = 0.3 -0.5 $$\mathrm{cm}^{-1}$$ cm - 1 at $$T=300$$ T = 300 K and $$\alpha =0.4$$ α = 0.4 -0.9 $$\mathrm{cm}^{-1}$$ cm - 1 at $$T=8.6$$ T = 8.6 K in the investigated wavelength range. With an absorption model based on transitions of free holes and holes trapped at an acceptor level, we conclude that the absorption due to free holes at $$T=150$$ T = 150 -300 K and that due to trapped-holes at $$T<50$$ T < 50 K are dominant absorption causes in CdZnTe. We also discuss a method to predict the CdZnTe absorption coefficient at cryogenic temperature based on the room-temperature resistivity.

INDUCED INFRARED ABSORPTION OF DEUTERIUM IN DEUTERIUM – FOREIGN GAS MIXTURES

1966 ◽  
Vol 44 (11) ◽  
pp. 2893-2903 ◽  
Author(s):  
S. T. Pai ◽  
S. Paddi Reddy ◽  
C. W. Cho
Keyword(s):  
Absorption Band ◽  
Binary Mixtures ◽  
Infrared Absorption ◽  
Room Temperature ◽  
The Other ◽  
Absorption Profile ◽  
Absorption Coefficients ◽  
Helium Mixtures ◽  
Experimental Values ◽  
The Individual

The pressure-induced fundamental infrared absorption band of deuterium was studied in deuterium–helium, deuterium–argon, and deuterium–nitrogen mixtures at pressures up to 1 200 atm at room temperature. The enhancement absorption profile of each mixture shows a well-resolved splitting of the Q branch into two components QP and QR. While the enhancement contours of deuterium–helium mixtures do not exhibit any absorption peaks corresponding to the O and S branches, those of the other two binary mixtures show a pronounced S(2) peak and an indication of several other O and S peaks of the band. Integrated absorption coefficients of the band have been measured for all the mixtures, and the binary and ternary absorption coefficients were determined. The theory of Van Kranendonk and the available molecular parameters of deuterium and the perturbing gases were used to calculate the binary absorption coefficients of the individual lines of the O and S branches and of the quadrupole part of the Q branch of the band in all three binary mixtures. Using these calculated values and the experimental values of the total binary absorption coefficients of these mixtures, the overlap parts of the binary absorption coefficients of the Q branch were estimated.

Infrared Absorption Coefficients for Certain Pollutant Gases

1972 ◽  
Vol 26 (3) ◽  
pp. 372-378 ◽  
Author(s):  
P. Campani ◽  
C. S. Fang ◽  
H. W. Prengle
Keyword(s):  
Infrared Spectroscopy ◽  
Quantitative Analysis ◽  
Path Length ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Optical Path Length ◽  
Optical Path ◽  
Absorption Coefficients ◽  
Wide Range ◽  
Pollutant Gases

Quantitative analysis of gas mixtures by infrared spectroscopy requires a knowledge of the absorption coefficients,: kν−, as a function of optical path length and temperature. For the majority of pollutant gases, information is scarce or incomplete. The objective of this work was to determine absorption coefficients for CH4, C2H4, CO2, CO, SO2, NO2, NO, and H2S. Measurements were made at room temperature and elevated temperatures for certain wave lengths, and kν− was determined over a very wide range of optical path length, x. The validity of the Bouguer-Beer law was confirmed for a limiting range of x, and for larger values of x, kν− decreased and was correlated as a function of x and T.

scholarly journals Оптические свойства фазопеременных материалов системы германий--сурьма-теллур составов Ge-=SUB=-14-=/SUB=-Sb-=SUB=-29-=/SUB=-Te-=SUB=-57-=/SUB=- и Ge-=SUB=-15-=/SUB=-Sb-=SUB=-15-=/SUB=-Te-=SUB=-70-=/SUB=- в дальнем инфракрасном диапазоне

2021 ◽  
Vol 55 (7) ◽  
pp. 542
Author(s):  
В.А. Рыжов ◽  
Б.Т. Мелех ◽  
Л.П. Казакова
Keyword(s):  
Amorphous Alloy ◽  
Infrared Absorption ◽  
Crystalline State ◽  
Room Temperature ◽  
Torsional Vibrations ◽  
Phonon Modes ◽  
Absorption Bands ◽  
Structural Units ◽  
Chalcogenide Alloys ◽  
Infrared Absorption Spectra

Abstract Infrared absorption spectra of chalcogenide alloys of the GST system with the compositions Ge14Sb29Te57 and Ge15Sb15Te70 in the amorphous and crystalline state were measured and analyzed in the range of 20 – 400 cm– 1 (0.6 – 12 THz) at room temperature. Absorption at these frequencies is due to the manifestation of correlated torsional vibrations of structural units of the amorphous alloy and phonon modes of the crystal. The performed assignment of absorption bands and the revealed differences in the IR spectra make it possible to more confidently represent the possible molecular mechanism of reversible amorphous-crystalline transformations in the studied phase-changing materials

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