Time resolved molecular-beam mass spectrometry

TIME-RESOLVED MOLECULAR BEAM MASS SPECTROMETRY OF TRANSIENT COMBUSTION PHENOMENA... 

ABSTRACT. We describe an apparatus by which the detonation products of an explosive can be identified and whose relative concentrations can be determined quantitatively. These measurements can be made on products that have been formed in less than one microsecond after the passage of the detonation wave. The technique is based on the rapid quenching of chemical reactions by virtue of the free expansion of the products into vacuum. Of course, products that have been formed over a longer period of time and under different pressure/temperature conditions can also be studied. Time resolved molecular-beam mass spectrometry is used, so that whether detonation occurred or not in forming the products can be determined. We describe optical techniques, principally Schlieren photographs, that also confirm detonation. We report measurements made on six standard explosives, PETN, RDX, HMX, HNS, TNT and TATB, and one research explosive, nitric oxide. For none of the standard explosives do we measure product distributions that agree with model predictions based on equilibrium assumptions. A computer model of the free expansion is described briefly and its importance to the interpretation of the data is emphasized. 

The spectroscopic and time-resolved studies of ESPT reactions in gas-phase clusters have provided significant information regarding the proton transfer mechanism between an excited molecule and a cluster of solvent molecules at a molecular level [15]. The resonant two-photon ionization method combined with mass spectrometry was used to measure the S, spectra of various clusters. Phenol (PhOH) and naphthol (NpOH) complexed with a variety of solvents were investigated by using molecular beam mass spectrometry and molecular beam... 

Figure 4.2. Experimental set-up for kinetic studies of SiHj reactions by excimer laser photolysis in a tubular slow-flow reactor with time-resolved detection by molecular beam sampling, near-threshold ionization electron impact mass spectrometry...

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