Pyrolysis nozzles coupled to a microwave spectrometer with stark modulation for the detection of transients species in a supersonic expansion

Two types of pyrolysis nozzles have been constructed and coupled to a new S tark modulated microwave spectrometer. The nozzles were tested on their abi lity to generate rotationally cooled transient species through a supersonic expansion. The transients species vinylamine, thioketene and ketene were g enerated and detected using nozzle temperatures ranging from 400-800 degree sC. Pyrolysis temperatures were generally lower than those used in normal f low pyrolysis experiments and rotational temperatures of ca. 10 K were achi eved. A preliminary investigation of the jet nozzle pyrolysis of 3-methyl-4 -hydroxy-iminoisoxaline-5-one was carried out and showed a different distri bution of CHNO pyrolysis products to that observed in previous low pressure studies.