DIAGNOSTIC TESTS OF A COLLISIONAL COOLING CELL USLD IN AN FTIR SPECTROMETER
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Date
1997
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Publisher
Ohio State University
Abstract
A new, liquid helium cooled collisional cooling cell has been construeted for use in spectral simplification experiments. The cell was cooled in a Janis vaporization cryostat and spectra were measured using a Bruker high resolution Fourier transform infrared spectrometer. Diagnostic tests of this cell using $C_{2}H_{2}, N_{2}O$, and $CCIF_{3}$ injected into a helium buffer gas show that the cell can be a useful tool for future simplification experiments. The initial failures and later successes of these tests revealed important information on the required operational parameters. Near-infrared measurements of $C_{2}H_{2}$ seemed to show only moderate cooling of the gas. However, in the overtone region, the S/N ratio was not adequate for useful diagnostics, and the spectrum was only observed for excessive injector flow rates. In the mid-infrared region, measurements of $N_{2}O$ yielded very acceptable rotational temperatures $(T_{rot} = 76 K $ for $T_{cell} =50 K)$. Measurements of $CCIF_{3}$ lines were taken to demonstrate the capabilities of collisional cooling with this system for spectral simplification.
Description
Author Institution: Department of Physics, The Ohio State University; Physikalisch-Chemistches Institut, Justus-Liebig-Universit\""at