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.

scholarly journals Analysis of new species retrieved from MIPAS

2014 ◽  
Vol 56 ◽  
Author(s):  
Shaomin Cai ◽  
Anu Dudhia
Keyword(s):  
Fourier Transform ◽  
New Species ◽  
High Resolution ◽  
Trace Gases ◽  
Michelson Interferometer ◽  
Emission Spectra ◽  
Fourier Transform Spectrometer ◽  
Mid Infrared ◽  
The Third ◽  
Atmospheric Sounding

The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instrument which operated on the Envisat satellite from 2002-2012 is a Fourier transform spectrometer for the measurement of high-resolution gaseous emission spectra at the Earth's limb. It operates in the near- to mid-infrared, where many of the main atmospheric trace gases have important emission features. The initial operational products were profiles of Temperature, H2O, O3, CH4, N2O, HNO3, and NO2, and this list was recently extended to include N2O5, ClONO2, CFC-11 and CFC-12. Here we present preliminary results of retrievals of the third set of species under consideration for inclusion in the operational processor: HCN, CF4, HCFC-22, COF2 and CCl4.

The spectrum of gaseous methane at 77 K in the 1.1 – 2.6 μm region: a benchmark for planetary astronomy

1989 ◽  
Vol 67 (11) ◽  
pp. 1027-1035 ◽  
Author(s):  
A. R. W. McKellar
Keyword(s):  
Fourier Transform ◽  
High Resolution ◽  
Low Temperature ◽  
Spectral Resolution ◽  
Fourier Transform Spectrometer ◽  
Absorption Cell ◽  
Model Calculations ◽  
Testing Model ◽  
Medium Resolution ◽  
Spectrometer Data

The spectrum of CH4 obtained in CH4 plus N2 mixtures at a temperature of 77 K has been recorded with a spectral resolution of 0.14 cm−1 in the region 3800 to 9100 cm−1. The experiments were performed with long paths (66 or 88 m) in a cooled absorption cell using a Fourier-transform spectrometer. Data are presented here at low and medium resolution, and examples of some spectral regions are also shown at high resolution. The complete results are available from the author in an Appendix. Comparisons are made with previous model calculations of CH4 absorption, and with the observed spectrum of Neptune's satellite, Triton. The results should be useful for the interpretation of the spectra of Triton, Titan, and Pluto. They will also be of value for testing model calculations of low-temperature CH4 absorption, which, thus verified, can be used with greater confidence to analyze observations of Jupiter, Saturn Uranus, and Neptune.

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.

Investigation of the Stark Shift of the Benzene-d1 101 — 000 Rotational Transition by Microwave Fourier Transform Spectroscopy

1987 ◽  
Vol 42 (1) ◽  
pp. 72-78 ◽  
Author(s):  
Eckhard Fliege ◽  
Helmut Dreizler
Keyword(s):  
Fourier Transform ◽  
Dipole Moment ◽  
Absorption Coefficient ◽  
Rotational Transition ◽  
Stark Shift ◽  
Permanent Dipole Moment ◽  
Fourier Transform Spectrometer ◽  
Deuterium Substitution ◽  
Set Up ◽  
Sample Pressure

The Stark shift of the J'K′_K′+ - J″K_K″+ = 101 - 000 transition of benzene-d1 was investigated to determine the dipole moment caused by deuterium substitution. A modified set-up of the microwave Fourier transform spectrometer was used to be able to apply the necessary Stark voltage and to increase the sensitivity of the instrument. The resulting permanent dipole moment is μa = 0.00810(28) D corresponding to an absorption coefficient of ymax = 2.8 • 10-12 cm-1 , determined at a sample pressure of 1.5 mTorr, for that line.

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