Knowledge Bank

In a previous $studya$ we had reported $N2$-broadening and pressure-induced shift coefficients for 34 rovibrational transitions in the $\mathrm{<mrow\; data-mjx-texclass="ORD">12</mrow>}C16O2\nu 3$ fundamental band near $4.3\mu m$. These parameters were determined from spectra recorded with the McMath-Pierce Fourier transform spectrometer (FTS) of the National Solar Observatory on Kitt Peak, Arizona. We now report similar measurements of $N2$-broadening and shifts for transitions up to $J\prime \prime =56$ in the $\mathrm{<mrow\; data-mjx-texclass="ORD">13</mrow>}C16O2\nu 3$ fundamental band, plus determinations of $N2$-broadening coefficients in the $\mathrm{<mrow\; data-mjx-texclass="ORD">13</mrow>}C16O2\nu 2+\nu 3-\nu 2$ hot band and the $\mathrm{<mrow\; data-mjx-texclass="ORD">13</mrow>}C16O18O\nu 3$ fundamental band. We also made new measurements of $N2$-broadening and pressure-induced shift coefficients for rovibrational transitions up to $J\prime \prime =46$ in the $\mathrm{<mrow\; data-mjx-texclass="ORD">12</mrow>}C16O2\nu 3$ fundamental band. These results were obtained from simultaneous analysis of five absorption spectra using a multispectrum nonlinear least-squares $techniqueb$. A 4.08 cm sample cell at room temperature was used to record all of the spectra at $0.003cm-1$ resolution with the McMath-Pierce FTS. This data set includes one low pressure (0.15 Torr) spectrum obtained with a $90$-enriched $CO2$ sample and four spectra of lean mixtures of the same $\mathrm{<mrow\; data-mjx-texclass="ORD">13</mrow>}CO2$ sample in $N2$. Total pressures of the mixtures were between 101 Torr and 464 Torr. Because of the isotopic sample used, the $\nu 3$ fundamental bands of $\mathrm{<mrow\; data-mjx-texclass="ORD">12</mrow>}CO2$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">13</mrow>}CO2$ appeared together in the same spectra, and we were able to obtain a consistent set of line parameters for both molecules. The present measurements represent the first experimental determination of $N2$-broadening and pressure-induced shift coefficients in isotopic bands of $CO2$ in the $4.3\mu m$ region. The results obtained for the various bands will be compared with each other, with the values in the HITRAN $databasec$, and with available values reported in the literature.