, V.B.4.a.3 Analysis
If the absorption coefficients of two lines (one of which is assigned and thus has known lower state energy and linestrength) are measured at two temperatures, the lower state energy and line strength for the unassigned line can be calculated [1, 2]. If many assigned reference lines are used and many temperatures observed, the procedure is more robust and provides experimental measurement of its accuracy. Typically, 100 – 300 assigned lines are selected that are included in the QM catalogs [3, 4]. Since these reference lines have known strengths Sijµ2 and lower state energy levels El from the QM analyses, and Doppler widths dvD and line frequencies n0 from the known temperature and measured frequencies of our experiment, we can use a fit of their measured peak absorbance,
,
Figure V.B.4.a.3-1
to obtain the spectroscopic temperature T and nL/Q, where n is the number density of the molecules, L the effective path length of the spectroscopic cell, and Q the molecular partition function. This fit is performed for each of the 400 - 1200 spectra obtained over the temperature range.
Next we use two complimentary analysis procedures, both based on equation (V.B.4.a.3-1), to provide the astrophysically meaningful data.
V.B.4.a.3.i A Line List Catalog
V.B.4.a.3.ii A Spectral Point-by-Point Catalog
Back to V.B.Astronomical Spectroscopy
[1] I.R. Medvedev, F.C. De Lucia, Astrophys. J., 656 (2007) 621-628.
[2] S.M. Fortman, I.R. Medvedev, C.F. Neese, F.C. De Lucia, Astrophys. J., 714 (2010) 476-486.
[3] H.S.P. Muller, F. Schloder, J. Stutzki, G. Winnewisser, J. Mol. Struct., 742 (2005) 215-227.