The Thermal Decomposition of TNAZ

A detailed description of the molecular beam apparatus used, the rotating source machine, is available elsewhere [10]. For the present discussion a general outline of the salient features will be given, referring to the schematic diagram in Fig. 3. The important parts of the rotating source machine are labeled with numbers in this diagram. 

The molecular beam is formed by supersonic expansion from a heated oven source (i), shown in Fig. 3. The expansion is then collimated by a skimmer to form the molecular beam solid Une) as it passes from the source chamber (2) into the source differential region (J). From there the molecular beam passes through a second skimmer into the main chamber 4). The laser light travels in a direction perpendicular to the plane of the drawing in Fig. 3 and crosses the molecular beam at (5). This point is also on the axis of the detector, which is denoted by the dashed line. The oven source and separately pumped source and source-differential chambers are rotatable as a unit about the axis down which the laser beam travels. Ths rotation allows the molecular beam to detector angle 0 to be varied. 

The molecular beam apparatus is constructed such that the molecular beam source and source differential region may be rotated about the line upon which the laser approaches the molecular beam crossing. This is done so that the molecular beam-to-detector axis angle may be varied. 

From measuring the time-of-flight spectrum of a chopped molecular beam sent directly into the detector, it is found that the molecular beam has an average velocity of 1.1 xlO cm/sec with a velocity spread of 23 r tfull width). This information is used later in the analysis of the data. 

From the TNAZ mass spectrum obtained from the molecular beam time-of-flight measurements, it is found that the compound easily fragments upon ionization. In fact the signal at the parent mass-to-charge ratio (wi/e= 192) was only 1% of that obtained at the most abundant peals, of NO2 (m/e = 46). TTbat the decomposition of the parent molecule was 

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Later studies investigated the thermal decomposition of TNAZ using photofragmentation translational spectroscopy. The details are presented in the following section by first describing the experimental technique used in some detail. This is followed by a presentation of the experimental results that include the time-of-fllght spectra collected under conditions of high- and low-laser fluence. Then the forward convolution method of... 

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