AN ANALYSIS OF THE CHEMICAL COMPOSITION OF INTERSTELLAR GAS CLOUDS USING FORMALDEHYDE ABSORPTION SPECTRA.

National Radio Astronomy Observatory is operated by Associated Universities, Inc., under contract with the National Science Foundation. Present address of L.E. Snyder: Center for Advanced Studies and Department of Astronomy, University of Virginia, Charlottesville, Virginia, 22903. $^{1}$ Lewis E. Snyder, David Buhl, B. Zuckerman and Patrick Palmer, Phys. Rev. Letters 22, 679 (1969). $^{2}$David Buhl, Lewis E. Snyder, B. Zuckerman and Patrick Palmer, Paper presented at the 129th Meeting of the American Astronomical Society, Honolulu, Hawaii, March 30-April 2, 1969. $^{3}$ T. Shigenari, J. Phys. Soc. Japan 23, 404 (1967). Present address of L.E. Snyder: Center for Advanced Studies and Department of Astronomy, University of Virginia, Charlottesville, Virginia, 22903.Author Institution: National Radio, Astronomy Observatory Green Bank; National Radio, University of Maryland; National Radio, University of ChicagoAbsorption spectra of the recently $reported^{1, 2}$ 4830 MHz transition of interstellar formaldehyde $(H_{2}CO)$ have been compared with spectra of other atomic and molecular constituents of the interstellar medium. Radial velocity correlations have given some new insight into the chemical composition of interstellar gas clouds and the astronomically determined rest frequency is found to be in excellent agreement with laboratory $measurement.^{3}$ Evidence of hyperfine splitting due to the spin rotation interaction has been observed in several interstellar $H^{2}CO$ clouds