Collision-induced absorption in ethylene in the microwave and far-infrared regions

1981 ◽  
Vol 59 (1) ◽  
pp. 57-65 ◽  
Author(s):  
I. R. Dagg ◽  
L. A. A. Read ◽  
B. Andrews
Keyword(s):  
Fourier Transform ◽  
Far Infrared ◽  
Microwave Cavity ◽  
Fourier Transform Spectrometer ◽  
Density Range ◽  
Spectral Moments ◽  
Induced Absorption ◽  
Hcn Laser

The collision-induced rotation–translation spectrum of gaseous ethylene has been measured at 295 K over a density range from 3.7 to 23.9 amagat in the 40–360 cm−1 region and at densities up to 50 amagat at 2.3 cm−1 and at 29.6 cm−1. The measurements were made using a Fourier transform spectrometer, an HCN laser, and a microwave cavity technique. Two spectral moments of the observed spectrum have been determined and used in a recently developed theory to provide values for the components of the quadrupole tensor of ethylene: Qxx = −3.54 × 10−26, Qyy = 1.77 × 10−26, Qzz = 1.77 × 10−26 esu. These values are compared with those obtained by other workers using different methods. The z direction is along the C–C axis, the y direction is in the plane of the molecule, and the x axis is perpendicular to the plane of the molecule.

Collision-induced absorption in ethane in the microwave and far-infrared regions

1982 ◽  
Vol 60 (1) ◽  
pp. 16-25 ◽  
Author(s):  
I. R. Dagg ◽  
W. Smith ◽  
L. A. A. Read
Keyword(s):  
Absorption Spectrum ◽  
Far Infrared ◽  
Fourier Transform Spectrometer ◽  
Density Range ◽  
Fir Laser ◽  
Quadrupolar Interaction ◽  
Induced Absorption ◽  
Upper Limit ◽  
Experimental Values ◽  
Microwave Techniques

The collision-induced absorption spectrum of gaseous ethane has been measured at 295 K over a density range from 12 to 45 amagat in the 50–360 cm−1 region and at densities up to 59 amagat at 4.6, 17.4, and 29.6 cm−1. The measurements were made using a Fourier transform spectrometer, an HCN laser, a FIR laser, and microwave techniques. A collision-induced torsional absorption is observed which is centred at 280 cm−1 and is superimposed on the collision-induced rotation–translation absorption. Theoretically, the latter absorption can be ascribed to quadrupolar interaction. This theory has been used to extract estimates for the quadrupole moment of ethane. The results provide an upper limit for the value of Q = −1.28 × 10−26 esu. Lower estimates are also given which reflect a larger contribution to the absorption from the torsional band by using the known absorption profiles for N2 and C2H4. These estimates are compared with other theoretical and experimental values.

Imaging Fourier transform spectrometer with photoconductive detector arrays: an application to the AKARI far-infrared instrument

2008 ◽  
Author(s):  
Mitsunobu Kawada ◽  
Hidenori Takahashi ◽  
Noriko Murakami ◽  
Yoko Okada ◽  
Akiko Yasuda ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Far Infrared ◽  
Fourier Transform Spectrometer ◽  
Detector Arrays ◽  
Photoconductive Detector

Design of an efficient broadband far-infrared fourier-transform spectrometer

1999 ◽  
Vol 38 (18) ◽  
pp. 3945 ◽  
Author(s):  
Bruno Carli ◽  
Alessandra Barbis ◽  
John E. Harries ◽  
Luca Palchetti
Keyword(s):  
Fourier Transform ◽  
Far Infrared ◽  
Fourier Transform Spectrometer

Far-infrared high-resolution Fourier transform spectrometer

1987 ◽  
Vol 26 (18) ◽  
pp. 3818 ◽  
Author(s):  
Bruno Carli ◽  
Massimo Carlotti ◽  
Francesco Mencaraglia ◽  
Enzo Rossi
Keyword(s):  
Fourier Transform ◽  
High Resolution ◽  
Far Infrared ◽  
Fourier Transform Spectrometer

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.

Collision-induced absorption in nitrogen at low temperatures

1985 ◽  
Vol 63 (5) ◽  
pp. 625-631 ◽  
Author(s):  
I. R. Dagg ◽  
A. Anderson ◽  
S. Yan ◽  
W. Smith ◽  
L. A. A. Read
Keyword(s):  
Quadrupole Moment ◽  
Laser System ◽  
Far Infrared ◽  
Microwave Cavity ◽  
Jones Potential ◽  
Induced Absorption ◽  
Line Shapes ◽  
Theoretical Predictions ◽  
Theoretical Line

The collision-induced absorption (CIA) spectrum for nitrogen has been measured in the spectral region below 360 cm−1 at 126, 149, 179, and 212 K. The measurements have been obtained using Fourier transform infrared (FTIR) techniques, a far infrared (FIR) laser system operating at 84.2 and 15.1 cm−1, and microwave cavity techniques. The experimental line shapes have been compared with the theoretical predictions of Joslin, based on Mori theory, and of Joslin and Gray, based on information theory alone. The data have been used to determine the quadrupole moment employing various intermolecular potentials. One Lennard–Jones potential has resulted in a quadrupole moment of 1.51 B, the value that was used in generating the theoretical line shapes. These results, when combined with our forthcoming measurements on nitrogen mixed with methane and argon, may be helpful in determining the role of CIA in calculating the opacity of some planetary atmospheres.

Temperature dependent collision-induced absorption in nitrogen

1984 ◽  
Vol 62 (4) ◽  
pp. 338-347 ◽  
Author(s):  
N. W. B. Stone ◽  
L. A. A. Read ◽  
A. Anderson ◽  
I. R. Dagg ◽  
W. Smith
Keyword(s):  
Close Agreement ◽  
Far Infrared ◽  
Intermolecular Potential ◽  
Fourier Transform Spectrometer ◽  
Fir Laser ◽  
Complete Spectrum ◽  
Temperature Dependent ◽  
Induced Absorption ◽  
Different Temperatures ◽  
Microwave Data

The collision-induced rotational translational spectrum of gaseous N2 has been measured in the temperature range 228–343 K at six different temperatures. The measurements were made with a Fourier transform spectrometer in the 25 to 360 cm−1 region and at 15.1 and 84.2 cm−1 with far infrared (FIR) laser. Previously obtained microwave data at 2.3 and 4.7 cm−1 have been used in defining the complete spectrum. Using a recently developed theory for quadrupolar-induced absorption, we find that the calculated quadrupole moment is independent of temperature and has a magnitude in close agreement with the recommended values of several other workers; i.e., Q = 1.46 B. The calculated value depends on the particular form of the intermolecular potential and this dependence is examined in some detail. A contribution to the absorption originating primarily from hexadecapolar and overlap induction has been observed in agreement with theoretical estimates and leads to an estimated value for the hexadecapolar moment [Formula: see text].

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