Cryogenic absorption cells operating inside a Bruker IFS-125HR: First results for 13CH4 at 7 μm

Details Cryogenic absorption cells operating inside a Bruker IFS-125HR: First results for 13CH4 at 7 μm Cryogenic absorption cells operating inside a Bruker IFS-125HR: First results for 13CH4 at 7 μm

Aug 2010

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010jmosp.262..122s&link_type=abstract

Journal of Molecular Spectroscopy, Volume 262, Issue 2, p. 122-134.

Computer Science

2

Scientific paper

New absorption cells designed specifically to achieve stable temperatures down to 66 K inside the sample compartment of an evacuated Bruker IFS-125HR Fourier transform spectrometer (FTS) were developed at Connecticut College and tested at the Jet Propulsion Laboratory (JPL). The temperature stabilized cryogenic cells with path lengths of 24.29 and 20.38 cm were constructed of oxygen free high conductivity (OFHC) copper and fitted with wedged ZnSe windows using vacuum tight indium seals. In operation, the temperature-controlled cooling by a closed-cycle helium refrigerator achieved stability of ±0.01 K. The unwanted absorption features arising from cryodeposits on the cell windows at low temperatures were eliminated by building an internal vacuum shroud box around the cell which significantly minimized the growth of cryodeposits. The effects of vibrations from the closed-cycle helium refrigerator on the FTS spectra were characterized. Using this set up, several high-resolution spectra of methane isotopologues broadened with nitrogen were recorded in the 1200-1800 cm-1 spectral region at various sample temperatures between 79.5 and 296 K. Such data are needed to characterize the temperature dependence of spectral line shapes at low temperatures for remote sensing of outer planets and their moons. Initial analysis of a limited number of spectra in the region of the R(2) manifold of the ν4 fundamental band of 13CH4 indicated that an empirical power law used for the temperature dependence of the N2-broadened line widths would fail to fit the observed data in the entire temperature range from 80 to 296 K; instead, it follows a temperature-dependence similar to that reported by Mondelain et al. [17,18]. The initial test was very successful proving that a high precision Fourier transform spectrometer with a completely evacuated optical path can be configured for spectroscopic studies at low temperatures relevant to the planetary atmospheres.

Affiliated with

Also associated with

No associations

Rating

Cryogenic absorption cells operating inside a Bruker IFS-125HR: First results for 13CH4 at 7 μm does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Cryogenic absorption cells operating inside a Bruker IFS-125HR: First results for 13CH4 at 7 μm, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cryogenic absorption cells operating inside a Bruker IFS-125HR: First results for 13CH4 at 7 μm will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-982858