Simulation of ion trajectories during Laser Ablative Mass Spectrometry of Energetic Materials.

The high power laser incident on an Energetic Materials,EM creates temperatures of the order of few eV to tens of KeV and pressures of the order of MPa to GPa. The initial conditions of P,T are known to play crucial role in the decomposition pathway of EMs, which in turn are controlled by incident laser parameters. The laser ablative pressures and temperatures will vary the initial conditions of EMs and result in completely different pathways in contrast to the well-known thermal decomposition of EMs [1]. Study of the common gaseous by-products such as Carbon Dioxide, Water, Carbon Monoxide, Nitrogen Dioxide from the pulsed laser induced decomposition,LID of Energetic Materials,EM simulated using COMSOL-Multiphysics is presented. The laser induced pressure and temperature on the gas molecules were parameterized in terms of varying initial kinetic energy of oxides of C,H,N over the range of 0.5eV to 5eV. The evolution of various end products at the detector of a Quadrupole Mass Spectrometer, QMS is simulated. The stability zone and effect of initial velocities of the ions on the stable trajectory of ions were determined from the simulations.
References :
1.Richard Behrens,Jr. J.Phys.Chem.1990, 94, 67-7-6718.