Knowledge Bank

The $CO2$ bands between 3450 $cm-1$ and 3770 $cm-1$ were studied at temperature of $625\circ K$ with a spectral resolution of $0.01cm-1$. A multitraversal absorption cell which can be operated at a temperature up to $1000\circ K$, was used for the study, together with a high-resolution Fourier interferometer $spectrometer.1,2$ The spectra which were measured with the $CO2$ concentration of approximately $1.4\times 1020$ molecules and the total pressure of 22 Torr at $625\circ K$, produced more than 2000 lines, out of which about 30 $\mathrm{<mrow\; data-mjx-texclass="ORD">12</mrow>}C16O2$ bands were identified. Several intense bands showed the transitions up to J = 80 level. The observed data were compared with the synthesized spectra calculated using the $CO2$ line parameters listed on the AFGL atmospheric absorption line parameter $compilation,3$ and some discrepancies have been noted in the line positions. The spectral analysis of these observed bands will be presented together with the experimental details.