Near Infrared Absorption of Ethylene between 5500 cm−1 and 6500 cm−1 to High Pressures and Temperatures

1976 ◽  
Vol 80 (7) ◽  
pp. 650-656 ◽  
Author(s):  
M. Buback ◽  
F. W. Nees
Keyword(s):  
Infrared Absorption ◽  
Near Infrared ◽  
High Pressures ◽  
High Pressures And Temperatures

Near Infrared Absorption of Pure n-Heptane between 5000 cm 1 and 6500 cm-1 to High Pressures and Temperatures

1983 ◽  
Vol 38 (5) ◽  
pp. 528-532 ◽  
Author(s):  
M. Buback ◽  
A. A. Harfoush
Keyword(s):  
High Pressure ◽  
Infrared Absorption ◽  
Near Infrared ◽  
High Pressures ◽  
Kinetic Studies ◽  
Molar Absorptivity ◽  
High Pressure High Temperature ◽  
High Pressures And Temperatures ◽  
Combination Mode ◽  
Better Than

The near infrared absorption of pure n-heptane between 5000 cm-1 and 6500 cm-1 was measured up to 250 °C and to pressures of 2000 bar. The procedure for measuring vibrational intensities at high pressures and temperatures with a precision of better than ± 1% is described. The integrated “molar absorptivity of the combination mode va + vs of the methylene stretching fundamentals turns out to be independent of temperature and density. This offers important applications for high-pressure high-temperature thermodynamic and kinetic studies via quanti­tative near infrared spectroscopy.

scholarly journals Near Infrared Absorption of Ethylene between 8200 cm-1 and 9500 cm-1 to High Pressures and Temperatures

1976 ◽  
Vol 31 (12) ◽  
pp. 1690-1695 ◽  
Author(s):  
F. W. Nees ◽  
M. Buback
Keyword(s):  
Infrared Absorption ◽  
High Frequency ◽  
Near Infrared ◽  
High Pressures ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
Experimental Conditions ◽  
High Pressure High Temperature ◽  
Wide Range ◽  
Integrated Intensity

AbstractThe near infrared absorption of pure ethylene in the region of the second overtone of the C-H stretching fundamentals (8200 cm-1 to 9500 cm-1) was measured at supercritical temperatures (Tc = 9.5 °C) between 22 °C and 200 °C from 0.7 bar to 3000 bar. The density and temperature dependence of bandshape, maximum frequency and absorption intensity are reported and discussed. The bands observed within a wide range of experimental conditions are assigned to combination and overtone modes. The molar integrated intensity B̅λ determined between the wavelength of maximum absorption and the high frequency absorption boundary was observed to be independent of pressure and temperature. This enables spectroscopic concentration determinations on ethylene in high pressure - high temperature phase equilibria and reactions.

Infrarotabsorption von reinem Dichlormethan bis zu hohen Drücken und Temperaturen / Infrared Absorption of Pure Dichloromethane Measured up to High Pressures and Temperatures

1979 ◽  
Vol 34 (12) ◽  
pp. 1489-1495
Author(s):  
M. Buback ◽  
E. U. Franck ◽  
H. Lendlc
Keyword(s):  
High Pressure ◽  
Single Crystal ◽  
Infrared Absorption ◽  
High Pressures ◽  
Molar Absorptivity ◽  
Polar Materials ◽  
Bending Mode ◽  
High Pressures And Temperatures ◽  
Window Material ◽  
Repulsive Forces

Abstract The infrared absorption of the ν1 and ν6 stretching fundamentals and of the ν2 CH2-bending mode in pure dichloromethane has been measured up to pressures and temperatures of 2 kbar and 200 °C, respectively. The optical high pressure cells were equipped with CaF2 single crystal windows. The applicability of this window material at high pressures and temperatures was investigated.With increasing density the wavenumbers of maximum absorption of ν1 and ν2 shift to lower and of ν6 to higher values. The integrated molar absorptivity of ν2 and ν6 increases with in-creasing density while it remains nearly constant for the ν1 vibration.The results obtained for the C-H modes clearly differ from those measured for O-H or N-H vibrations in polar materials. They are attributed to the action of repulsive forces in dense CH2Cl2.

Infrared Absorption of Concentrated Aqueous LiCl Solutions to High Pressures and Temperatures

1980 ◽  
Vol 35 (5) ◽  
pp. 549-555
Author(s):  
V. M. Valyashko ◽  
M. Buback ◽  
E. U. Franck
Keyword(s):  
Infrared Absorption ◽  
High Pressures ◽  
Molar Absorptivity ◽  
Measured Data ◽  
High Salt ◽  
Maximum Absorption ◽  
Mole Percent ◽  
High Pressures And Temperatures

Abstract The infrared absorption of the O-D stretching fundamental of HDO in concentrated aqueous (HDO/H2O) LiCl solutions to a maximum of 40 mole percent salt has been measured. Data for the wavenumber of maximum absorption, ν̄(max), and for the integrated molar absorptivity B up to pressures and temperatures of 2800 bar and 350 °C, respectively, are reported and discussed. Toward high salt concentrations, the dependence of ν̄(max) on temperature and on LiCl concentration decreases. The wavenumber data indicate a transition from "water-like" to "melt-like" behaviour at about 12 to 15 mole percent LiCl.

Infrared Absorption of Concentrated Aqueous NaClO4 Solutions to High Pressures and Temperatures

1981 ◽  
Vol 36 (11) ◽  
pp. 1169-1176 ◽  
Author(s):  
V. M. Valyashko ◽  
M. Buback ◽  
E. U. Franck
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Infrared Absorption ◽  
High Pressures ◽  
Molar Absorptivity ◽  
Wave Number ◽  
Water Molecules ◽  
High Pressure High Temperature ◽  
High Pressures And Temperatures ◽  
Band Separation

The infrared absorption of the O-D stretching fundamental of HDO in concentrated aqueous (HDO/H2O)NaClO4 solutions up to 20 mole% salt has been measured. The data for the wave-number of maximum absorption, ν̅(max), and for the integrated molar absorptivity B up to pressures and temperatures of 2800 bar and 250 °C, respectively, demonstrate the importance of non-hydrogen-bonded interactions in aqueous perchlorate solutions. A non-continuous dis­tribution of the states of water molecules is clearly evident from the experimental spectra. A band separation using three Gaussian components proves the close similarity between the high-pressure high-temperature vibrational O-D infrared spectra of aqueous perchlorate solutions and the O-D Raman spectra of water and aqueous solutions.Results of the band separation together with literature Raman data provide some evidence that a transition from “water-like” to “melt-like” behaviour occurs in a fairly narrow concentra­tion region between 10 and 15 mole% salt.

Infrared absorption of MgO at high pressures and temperatures: A molecular dynamic study

2009 ◽  
Vol 131 (1) ◽  
pp. 014506 ◽  
Author(s):  
Gboyega A. Adebayo ◽  
Yunfeng Liang ◽  
Caetano R. Miranda ◽  
Sandro Scandolo
Keyword(s):  
Molecular Dynamic ◽  
Infrared Absorption ◽  
High Pressures ◽  
Dynamic Study ◽  
Molecular Dynamic Study ◽  
High Pressures And Temperatures
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