On Scalability of DFT-Calculated IR Spectra for Spectrum-Feature Extraction and Estimation of Dielectric Response

Extraction of spectrum features for target molecules from measured spectra, for purpose of their detection, can be achieved by comparison to template spectra within a spectrum database, which are sufficient approximations of dominant spectral features. This study continues presentation of the concept of using Density Functional Theory (DFT) to calculate template spectra for practical detection of target substances, by comparison with spectra within databases. DFT calculated spectra are well posed for comparison to measured spectra, as template spectra, to the extent of their scalability to larger space-time scales. Specifically, the focus of this study is scalability of DFT-calculated IR spectra with respect to meso and macro scales, characteristic of dielectric response as measured using different IR spectroscopies. A case study analysis concerning scalability of IR spectra for caffeine is described.