Knowledge Bank

Theoretical descriptions of the abundance and excitation of CO in interstellar clouds require accurate and complete information on many molecular properties. In particular, data such as line positions, line widths, and photoabsorption coefficients, which will allow the photodissociation rate for CO to be determined, are needed. We have measured photoabsorption cross sections for CO at a resolving power more than 20 times greater than that used in previous $work.1$ Most of the measurements were made with 6.65-m vertical-dispersion spectrograph/spectrometer at the Photon Factory of the National Laboratory for High Energy Physics, $Japan.2$ The theoretical resolution was less than $3\times 10-4$ nm, but we believe that the actual value was about $7\times 10-4$ nm. Our integrated cross section values will be compared to those of $ref.1$. This work is supported by NASA grant NSG-7304 to Harvard University and by JSPS Fellowship program.