UV excited electronic state decomposition of the energetic materials HMX and RDX using ns and fs laser spectroscopy

PHYS 418

Margo Greenfield, margo@lamar.colostate.edu1, Yuanqing Guo, yqguo18@lamar.colostate.edu1, and Elliot R. Bernstein, erb@lamar.colostate.edu2. (1) Department of Chemistry, Colorado State University, Ft. Collins, CO 80523, (2) NSF ERC for Extreme Ultraviolet Science and Technology/Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1872
Energy (ns) and time (fs) resolved photodissociation experiments are preformed to elucidate the mechanisms and dynamics of gas phase RDX/HMX decomposition from their excited electronic states. Intact HMX/RDX molecules are produced through laser desorption and supersonic expansion. UV (ns) photodissociation TOFMS experiments indicate NO is an initial decomposition product of HMX/RDX. Two potential NO intermediates, NO2 and HONO, have been ruled out. We suggest NO can be generated via an oxygen loss followed by a N-N bond scission or bond rearrangement forming R-N-O-NO followed by a loss of NO. Femtosecond pump-probe techniques have been used to measure the ultrafast photodissociation dynamics of RDX/HMX via the initial NO product at three wavelengths. Both pump-probe transients at non-resonant (228nm, 230nm) and resonant (226nm) absorption wavelengths indicate the dynamics of the HMX/RDX decomposition from the excited electronic state are faster than the time duration of our laser pulse (180fs).

Poster Session
7:30 PM-10:00 PM, Wednesday, 13 September 2006 Moscone Center -- Hall D, Poster

8:00 PM-10:00 PM, Monday, 11 September 2006 Moscone Center -- Hall D, Sci-Mix

Division of Physical Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006