New system for computer-aided infrared and Raman spectrum interpretation

A new software tool for the interpretation of infrared and Raman spectra has been developed. It makes use of fragment libraries comprising representative, carefully selected and refined data on characteristic vibration frequencies. The information was collected from multiple sources including published correlation tables and reference spectral databases. In an automatic mode, the system performs structure to spectrum verification to test the correspondence between a drawn chemical structure and an experimental spectrum. Computer-aided “manual” interpretation (an expert mode) facilitates the assignment of structural elements to spectral features by means of highlighting the library information over the spectrum. The interpretation performance was significantly improved compared to other systems of this type due to some novel features. These are original fragment structures incorporating the concept of nucleus (vibrating group) and a new system of queries (fuzzy atoms and bonds), as well as the inter-fragment logic, which make fragment formulation extremely flexible. ant methodological aspects of fragment library construction were considered, and the main principles of fragment formulation on the basis of experimental spectra were formalized. Principal component analysis (PCA) was applied to distinguish clusters formed by spectral responses due to a specific structural environment and to refine characteristic frequency regions.