Formaldehyde observations of giant molecular clouds

摘要: The excitation of H/sub 2/CO noted in the absorption toward a number Galactic continuum radio sources has been investigated on basis 2 cm and 6 K-doublet transitions. data are analyzed using 16-level collisional model rate coefficients Green et al. (1978). Median 2/ densities 90,000/cu for clouds near H I regions, 70,000/cu distant from II found. Estimates total ortho-H/sub column density have obtained, indicating that traces significant fraction seen CO. 41 references.