Estimation of dielectric-response for energetic materials using micro-to-macro scaling of DFT-calculated IR spectra

Detection of infrared (IR) spectrum features of target molecules can be achieved by comparison of experimentally measured spectra to template spectra within a database. The focus of this study is the scalability of density functional theory (DFT)-calculated IR spectra with respect to macroscales, characteristic of dielectric response as measured using IR spectroscopic methods, and demonstration that IR-spectrum databases can be constructed with respect to classes of target molecules, where DFT-calculated spectra provide a complementary extension of experimentally measured IR spectra. A case study analysis concerning IR-spectra scalability for a set of energetic materials is described. This analysis provides an example of calculating template spectra for potential detection of target molecules, where DFT-calculated IR spectra are frequently more convenient than laboratory measurements using IR spectroscopic methods. We have shown that DFT-calculated spectra can be included within template-spectrum databases, and their ability to show very good correlation with measured spectra.