Abstract : Thermal dissociation experiments using adiabatic compression as the means of heating were discontinued. A study of the adiabatic compression process in the TEI apparatus showed that because of the mechanical properties of the compressor and the high thermal conductivity of helium, a maximum temperature constant enough for kinetic and mechanism studies was not obtained. Modification of the apparatus to correct the difficulty does not seem warranted, and the use of argon rather that helium to minimize the heat loss problem would obscure the mass spectra used for analysis of the dissociation process. During this report period the flash photolysis of NF3 was reexamined, using a sample cell and flash tube arrangement that permitted the use of photolysis radiation as low as 1600A. No new features in the spectra of the flashed NF3 attributable to dissociation of the NF3 were observed. Equipment is being modified to allow flash photolysis kinetic spectroscopy spectra to be obtained in the vacuum ultraviolet region. (Author)