On the initial steps in the decomposition of energetic materials from excited electronic states

Decomposition studies of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX-C3H6N6O6, see Fig. 1) isolated in the gas phase and cooled in a supersonic expansion are reported for the excited electronic state near 225 nm. The RDX is handled safely and effectively through matrix-assisted laser desorption (MALD) of a thin film of RDX/R6G laser dye (1:1) adsorbed on an aluminum oxide coating on an aluminum drum. The aluminum oxide coating is generated by plasma electrolytic oxidation of aluminum. The combination of MALD and supersonic molecular beam techniques generates intact and cold RDX molecules isolated in the gas phase. Two basic conclusions are reached in this study. (1) Photodissociation of RDX at approximate to 225 nm generates NO as an initial product. (2) Nascent NO thus generated is vibrationally hot (T(vib)similar to 1800 K) and rotationally cold (T(rot)similar to 20 K). (C) 2000 American Institute of Physics. [S0021-9606(00)01142-9].