Characterization of organic materials by LIBS for exploration of correlation between molecular and elemental LIBS signals

The present study is performed for the preparation of a database by accumulating LIBS spectra of 4-nitroaniline and 4-nitrotoluene in air and argon. Changes in the behavior of the molecular bands of the C2 Swan system and CN violet system as well as of atomic lines of C, H and N in the LIBS signal are appreciable in argon. In order to explore the correlation between observed LIBS signal and molecular composition of these materials, normalized intensities of the emission lines have been estimated for each compound. It has been found that the relative rates of increase/decrease in the normalized intensities for all sets are higher for 4-nitrotoluene in argon. The cause of the higher rate for 4-nitrotoluene might be due to the possession of a distinctive functional group. The ultimate goal behind the whole study is to use this data-base as input for the discrimination of energetic materials.