Anti-Stokes fluorescence of PO-photofragments of organophosphates
S.M. Bobrovnikov, E.V. Gorlov, V.I. Zharkov, S.N. Murashko
V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, Tomsk, Russia
Keywords: organophosphate, trace, laser fragmentation, phosphorus oxide, PO-fragment, laser-induced fluorescence
Abstract
This paper demonstrates for the first time the possibility of exciting anti-Stokes fluorescence of PO-fragments of organophosphates. Using the example of drop-liquid traces of triethyl phosphate on a paper surface, it was determined that the relative population of vibrational levels v '' = 1 and v '' = 2 corresponds to a vibrational temperature of fragments of about 780 K. Indicators of significant violation of the equilibrium distribution of fragments over rotational energy levels were revealed. It has been determined that the method of exciting anti-Stokes fluorescence of PO-fragments of triethyl phosphate from the first vibrational level of the ground state X 2Π ( v '' = 1) to the zero vibrational level of the electronically excited state A 2Σ+ ( v ' = 0) provides the highest noise immunity of the LF/LIF method. The results can be used to select the optimal technique for exciting fluorescence of PO-fragments when implementing the LF/LIF method for remote detection of organophosphate traces.
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