Study Of Acetylene And Air Broadened Radiation Studies
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For the self- and air-broadened methane studies in 7.5-, 3.3-, and 2.3-μm regions, we will mostly make use of spectra recorded with the McMath-Pierce FTS at Kitt Peak, AZ and with the JPL Bruker IFS 125 HR FTS. Previously, some analysis has been done to determine broadening and shift parameters [23,24,32,34,35], in P- and R-branch manifolds, in several spectral regions. However, some dense spectral regions, such as Q-branches, remain unanalyzed and it may be necessary to record some new spectra at higher resolutions in these regions.
Analysis will be done using a multi-spectrum fitting technique  to retrieve the spectroscopic parameters for several transitions in the entire band of each molecule. This technique allows us to determine…show more content… The ν1+ ν3 band of acetylene with ν1 as the symmetric CH stretch and ν3 as the anti-symmetric stretch is one of the strong bands compared to other nearby bands. Therefore, it provides a good test case in different measurements. The measurements of self and foreign-gas broadening coefficients provide important information for the analysis of atmospheric spectra and on intermolecular potentials via theoretical calculations.
Despite the relatively large number of studies devoted to acetylene with different broadeneres such as N2, O2, air, He, Ne, Ar, Kr and Xe [48-52], the effect of CO2 on acetylene line shifts and broadening coefficients hasn’t been studied much at all. There are only single line shifts available in only two studies of one band [53,54]. Also, no studies of temperature dependence are available; therefore, if we measure pressure broadening coefficients at different temperatures, this will be of interest to the HITRAN community  if we provide line parameters for C2H2-CO2 mixtures for the ν1+ν3 band located in about 1.55 microns. Besides obtaining line shape parameters and their temperature dependences, using this measurement, we can test the accuracy of our experimental setup by calculating fundamental Boltzmann constant. The currently-accepted value for the Boltzmann constant (kB) published by the Committee on and Technology (CODATA) is 1.3806488×10-23 JK-1 with a relative uncertainty of