Radio astronomical observations of regions of star formation

This thesis presents the observations of radio wavelength atomic and molecular transitions towards regions of star formation. Radio wavelength measurements and upper limits for CH emission from diffuse interstellar clouds in the direction of nearby bright stars whose optical wavelength spectra exhibit the absorption lines of CH are reported. The F = 1-1 Λ-doublet transition at 3335.481 MHz was detected in the direction of 10 stars, and the F = 1-0 and F = 0-1 transitions at 3263.794 and 3349.193 MHz were detected in the direction of four stars. The ratio of the column densities of CH inferred from the 12 measurements in the two spectral regions is N/sub RAD//N/sub OPT/ = 1.68 +- 0.34, where the error bar denotes one standard deviation. These measurements ensure the compatibility of the reduction procedures in the two regions, and indicate that the oscillator strengths and excitation temperatures used in the reductions cannot be in error by more than a factor of 2. The relative abundance N/sub CH//N/sub H/ is an order of magnitude higher than that predicted by the grain-formation theory of CH. Estimates of the relative column densities of CH and carbon monoxide, CO, obtained from radio wavelength measurements of the diffuse interstellar clouds agree with those obtained from observations at optical and ultraviolet wavelengths with N/sub CH//N/sub CO/ approx. 0.03