Knowledge Bank

Spectroscopic constants and absolute intensities from more than 2150 transitions belonging to 52 bands of 7 isotopic species of carbon dioxide have been determined using a multispectrum nonlinear least-squares fitting $technique.1$ The spectral data ($0.01cm-1$ resolution) were obtained at room temperature and low pressure (<10 Torr) using the McMath-Pierce Fourier transform spectrometer of the National Solar Observatory on Kitt Peak, Arizona. A natural sample of carbon dioxide with absorption path lengths between 24 and 385m were used in recording the spectra. The first measurements have been made of the theoretically $predicted22\nu 2\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}+\nu 3$ "forbidden" band of $\mathrm{<mrow\; data-mjx-texclass="ORD">12</mrow>}CO2$. Two bands which have not been predicted so far, one belonging to $\mathrm{<mrow\; data-mjx-texclass="ORD">13</mrow>}CO2$ and the other to $\mathrm{<mrow\; data-mjx-texclass="ORD">13</mrow>}C\mathrm{<mrow\; data-mjx-texclass="ORD">16</mrow>}O\mathrm{<mrow\; data-mjx-texclass="ORD">18</mrow>}O$, have been identified. The measured line intensities obtained for each band have been analyzed to determine the vibrational band intensity and F-factor coefficients. The results are compared to the values used to calculate the intensities in the 1992 HITRAN $database2$. Simulations illustrating the differences in spectra predicted with the new lines and the HITRAN 1992 $lines2$ are presented along with comparisons to stratospheric and laboratory spectra.