The fragmentation processes of polyatomic molecules induced by an intense laser field exhibit sensitive dependence on the laser characteristics such as intensity, pulse duration, wavelength, and shape of the temporal pulse envelope. Adaptive laser pulse shaping can control the fragmentation of methyl/methoxy groups in dimethyl methylphosphonate (DMMP), a simulant for nerve agent sarin. The exploitation of the sensitivity of molecular fragmentation to laser pulse shapes represents a new way to discriminate molecular identity. Here we have shown manipulation of branching ratio M-(OCH3)+/M-(CH3)+, M-2(CH3)+/M-(CH3)+ and M-(OCH3)+/M-2(CH3)+ fragment ion ratios for DMMP in the presence of complex background in the extraction region of a TOF spectrometer using tailored femtosecond laser pulses. We suggest that the use of adaptive femtosecond laser pulse shaping coupled to TOF mass spectrometry is an accurate way to identify complex airborne organophosphate molecules similar to nerve agents.
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics