Surface characterization of nanoscale co-crystals enabled through tip enhanced Raman spectroscopy.

摘要: Atomic Force Microscopy coupled with Tip Enhanced Raman Spectroscopy (AFM-TERS) was applied to obtain information about the structure and surface composition of single nano co-crystals. For this purpose, a co-crystalline system consisting 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazatetracyclo-[5.5.0.03,11.05,9]-dodecane (CL-20) 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX) in molar ratio 2 : 1 (CL-20/HMX) chosen. CL-20/HMX nano-plates were prepared by spray flash evaporation. To ensure co-crystallinity nanostructures, powder X-ray diffraction AFM investigations performed. The results demonstrate that coherence lengths particle dimensions are on similar level though appear shorter than measured dimensions. According fact, defects inside co-crystals minimized. additionally proven confocal spectroscopy. Here, marker bands for pristine CL-20 HMX chosen which spectrum an intensity ∼2.5 : 1 (CL-20 : HMX). Afterwards performed AFM-TERS. Due sensitivity TERS, these experiments reveal intensities between inverts at nano-plate surfaces. Therefore, it is concluded co-crystal surfaces consist molecular layers HMX. A theoretical approximation normal coordinates investigated vibrations supports conclusion since can exclude occurrence inversion because given orientation scattering system. Based finding, impact ignition mechanism proposed, enabling explanation close values β-HMX CL-20/HMX.