THE PHOTOIONIZATION AND ABSORPTION SPECTRA OF CO AND $CO_{2}$ IN THE VACUUM ULTRAVIOLET

Abstract

“Absolute photoionization and absorption cross-sections of CO and $CO_{2}$ have been measured in the 600 to 1000{\AA} region using a 1-meter Seya Scanning vacuum ultraviolet monochromator with a resolution of 0.5A and the Hopfield continuum background light source. A path length of 40.6 cm was used with simultaneous detection of ion current and photon flux. In $CO_{2}$ band absorption was observed between 1000 and 716{\AA} with coefficients fluctuating between 700 and $3400 cm^{-1}$. Below 716{\AA} there was a region of continuous absorption with an average coefficient of about $550 cm^{-1}$. In $CO_{2}$ band absorption was observed from 1000 to 920{\AA}, continuous absorption from 920 to 840{\AA}, band absorption between 840 and 690{\AA}, and continuous absorption between 690 and 580{\AA}. The maximum and minimum coefficients in these regions were 3200 to $600 cm^{-1}$, 1900 to $260 cm^{-1}$, 3400 to $165 cm^{-1}$, and 600 to $500 cm^{-1}$, respectively. For both molecules the structure of the photoionization and absorption crosssection was similar beyond the ionization potential, but of different magnitude, indicating an ionization efficiency of less than 100%.”