Dane J. Phillips, Elizabeth A. Tanner, Frank C. De Lucia, Henry O. Everitt
A new method for highly selective remote sensing of atmospheric trace polar
molecular gases is described. Based on infrared/terahertz double resonance
spectroscopic techniques, the molecule- specific coincidence between the lines
of a CO2 laser and rotational-vibrational molecular absorption transitions
provide two dimensions of recognition specificity: infrared coincidence
frequency and the corresponding terahertz frequency whose absorption strength
is modulated by the laser. Atmospheric pressure broadening expands the
molecular recognition "specificity matrix" by simultaneously relaxing the
infrared coincidence requirement and strengthening the corresponding terahertz
signature. Representative double resonance spectra are calculated for
prototypical molecules CH3F and CH3Cl and their principal isotopomers, from
which a heuristic model is developed to estimate the specificity matrix and
double resonance signature strength for any polar molecule.
View original:
http://arxiv.org/abs/1202.0595
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