Simplification of the Molecular Vibration Analysis

The Physical Chemistry of Materials Energy and Environmental Applications 

As a result, specific kinds of vibration modes always appear at similar frequencies for different molecules then, it is feasible to construct a table of characteristic absorption frequencies. Typical absorption band tables for significant bonds included in polyatomic molecules are reported in ref. [58], Subsequently, using the typical absorption frequencies, it is relatively simple to recognize the occurrence of functional groups in unidentified compounds, and use this information to get structural information about these substances in order to identify them. 

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