Features Of The Raman Spectrums Of RDX And HMX Under Pressure And Features Of The Time-resolved Spectrums Of RDX And HMX

A lot of researches have been done about the chemical reactions of energeticmaterials, but most of them focus on the macro level or theoretical simulations,which indirectly leads to the lack of experimental supports and researches on themicro level. Due to their excellent stability and great power, RDX and HMX areboth typical and common energetic materials, which are widely used as the rawmaterials of secondary explosives.Firstly, by means of spontaneous Raman scattering spectroscopy, we do someresearch about the response properties of RDX and HMX under hydrostaticpressures successively. For both RDX and HMX, on the picture describing theresponse relationships between wave-number shifts of their Raman modes andgiven pressures, wave numbers of most Raman modes go through some abruptchanges, which is caused by the flaws existing in the samples. Commonlyspeaking, the flaws are known as the place where chemical reactions firstly happen.Therefore, the specific pressure zones are probably the threshold non-hydrostaticpressures which can cause the RDX samples to react chemically. However,energetic materials can endure much higher hydrostatic pressures than non-hydrostatic ones. So, as the hydrostatic pressures being raised furthermore, theflaws in the sample are offset by the structural changes of the flexible chemicalbonds, which results in the recover of their previous rising trends. But thesespecific pressures have not reached the threshold non-hydrostatic pressures of theHMX sample. In addition, by comparing the Raman spectrums under pressure ofHMX and RDX, we can also prove that HMX is more stable than RDX.Then, utilizing coherent anti-stokes Raman scattering spectroscopy(CARS)—both forward and backward, we discover some modes related to N-Nstretching and C-N stretching response differently from other modes. Additionally,the life time of the vibration modes are very short for both RDX and HMX, whichindirectly prove them to be insensitive explosives. Meanwhile, in the sameexperimental conditions, there are fewer and less intensive modes appearing in theCARS experiment for HMX than for RDX, which can also prove HMX is morestable than RDX.