Research On Molecular Structure Change And Stability Of Benzene Under Shock Loading Experiment

The properties and structural transformation of the energetic materials under high temperature and high pressure condition have received extensive attention of people. However, because of some of its own particularities and restrictions in terms of the experimental technology, there are no great progress have been made in the study of these materials for the study of scientific researchers. Therefore, the researchers try to find a kind of substance with a similar structure with energetic materials, hoping to provide certain reference for study of these materials. Benzene as organic compounds, with the most simple, typical structure in aromatic hydrocarbon compounds, so the various properties and molecular microstructure changes under high temperature and high pressure have been researched extensively. But, due to the limitation of experimental technology, only the macroscopic properties were obtained, without a breakthrough on the microstructure change. This paper, the Raman spectra for liquid benzene in a state of shock compression have been observed online by using the two-stage light gas-gun loading device with transient laser Raman test technology, a directed evidence was given for the problem about structural stability of benzene in shock compression experiment through observing the changes in peak shape and peak position for C-C stretching vibration mode(992cm-1) and C-H stretching vibration mode(3061cm-1).Based on the optimization of the structure of target, change the way of trigger and improve scattered light collecting system, we successfully realized the combination of two-stage light gas-gun with Raman testing system. And observed Raman spectroscopy online for liquid benzene in the range of7-21GPa using the system. The experimental results show that within the13GPa, Raman frequency shift linearly increased along with the change of pressure, and the magnitude of frequency shift is closely depend on molecular vibration modes. Besides, firstly clarified the structural changes of liquid benzene around13GPa using Raman spectrum technology, and explained the mechanism about the impact induced molecular structural changes of benzene liquid. Through the analysis of spectral signal, put forward the structure instability of benzene in the shock compression process can be divided into two stages: the first is rupture of C-H bond(13GPa), then is C-C bond(19GPa). Do the forecast for the composition of new material, from the experimental results we speculated that the products are a certain kind of carbon clusters which is similar to graphite, and the material is not transparent. The impact induced structural change of liquid benzene should be decided together by pressure and temperature.