Spectroscopic Data Computer Assisted

During the past five decades, spectroscopy has moved out from the laboratories of physicists and theoretical chemists into every area of analysis and chemical research. Applications vary from routine, single data point measurements for control of plant streams to structural analysis of complex molecules and conformational analysis of polymers. Enhancement of the sensitivity of all spectroscopic methods has been achieved through computer-assisted data handling. It is possible to find structural differences in polymers under different degrees of stress and to analyze for very low levels of chemical structures at surfaces and interfaces. For difficult structure determinations, data from several spectroscopic disciplines may be combined and require months or years of research. 

The goal of computer-assisted stmcture elucidation (CASE) is the derivation of all possible structures that are consistent with a set of spectroscopic data, with the minimum of intervention by the spectroscopist. If computer-assisted... 

Intelligent computer assisted interpretation of spectroscopic data should be based on the knowledge from large structure oriented data collections. Both the inspection of spectral features and the statistical evaluation of similar structures (from library searches) can provide a set of probability ranked substructures which are readily assembled to target structures. The idea of substructure analysis allows the chemist to combine the results of different interpretation strategies, different databases and different spectroscopic methods to yield the structural information desired. Thus in a multidimensional data system hke SPECINFO structural noise can be effectively suppressed, if all information available in the spectroscopic laboratory is combined in a central intelligent computer system. 

In resonance Raman spectroscopy, if the incident radiation is near a UV-vis absorption feature of the metal ion, the Raman scattering involving bonds in the immediate vicinity of the metal is greatly enhanced. This selectivity for the active site region is very useful in bioinorganic studies because the key absorptions are not buried under the multitude of absorptions from the rest of the protein. For iron proteins, Mossbauer measurements can help determine oxidation state and help distinguish 4- from 5- and 6-coordinate metals and hard from soft ligand environments. Computational data can assist the interpretation of both Mossbauer and X-ray spectroscopic data. 

---