AST 9530695 Two New Views of the Dense Interstellar Medium. Dr. Jaffe will utilize a proven, novel instrument on the CalTech Submillimeter Telescope and a big-beam Fabry-Perot at McDonald Observatory and at CTIO for a survey of the interstellar medium. The primary goal is to characterize the portion of the material in the dense interstellar medium where ultraviolet photons from young stars dominate the ionization state and energetics of the gas. Such regions are predominantly molecular, but the most common tracer of molecular material, CO, can be depleted or absent. The high electron densities in the ultraviolet influenced material may prevent it from participating in star formation. If this is the case, the abundance and nature of the material will play a role in determining the efficiency of star formation in molecular clouds. The approach of Dr. Jaffe's project is to determine the amount, distribution, and physical properties of the ultraviolet influenced molecular gas over large scales. =================================================