Carbon Dioxide in the Infra-Red Solar Spectrum

Abstract

Wave-length measurements are given for lines in thirteen vibration-rotation bands of carbon dioxide observed between 1.5\ensuremath{\mu} and 2.1\ensuremath{\mu} in the infra-red solar spectrum and in the laboratory. The observations were made with the McGregor spectrometer and Cashman cell of the McMath-Hulbert Observatory. Among the thirteen bands, seven originate from the ground state and two from the first excited state of ${\mathrm{C}}^{12}$${\mathrm{O}}_{2}^{16}$. The remaining four are identified with ground state transitions in the isotopic molecules ${\mathrm{C}}^{13}$${\mathrm{O}}_{2}^{16}$ and ${\mathrm{C}}^{12}$${\mathrm{O}}^{16}$${\mathrm{O}}^{18}$. The rotational constants ${\ensuremath{\alpha}}_{1}$, ${\ensuremath{\alpha}}_{2}$, and ${\ensuremath{\alpha}}_{3}$ have been determined from analysis of the rotational structures. The mean value found for ${B}_{000}$ is 0.3906 ${\mathrm{cm}}^{\ensuremath{-}1}$ and for the equilibrium position ${B}_{e}=0.3920$ ${\mathrm{cm}}^{\ensuremath{-}1}$.