Dynamics of TNT photo dissociation studied by femtosecond laser-mass spectroscopy

The purpose of this study is to establish the kinetic energy distribution of NO2 and NO as a product of photo-fragmentation of neat TNT or and TNT on Ottawa sand using femtosecond laser pulses for molecular dissociation and subsequent mass spectrometry measurements as a function of time. Photolysis experiments on TNT deposits irradiated with 100 femtosecond laser pulses at 400 nm and 266 nm wavelengths were performed. NO2 and NO were analyzed as key fragments. The obtained data showed that there are slight differences in the NO2 and NO speeds from TNT crystals and TNT deposited on sand and vapor phase of TNT. Those results indicate that the energetic processes that result in fragments ejection are different in all cases. In conclusion, photo-fragmentation using femtosecond lasers followed by mass spectrometry measurement is a sensitive approach for the kinetic energy distribution establishment of NO/NO2 fragments; besides, its effectiveness could be enhanced coupling it with another spectroscopic method for trace amounts detection of nitrorganic explosives. (Abstract shortened by UMI.)...