Abstract
Three types of analyses: generalized conventional spectroscopic analysis, statistical analysis, and hierarchical analysis, by which we aim to extract dynamical information from the complex spectrum of small polyatomic molecules are reviewed by referring to recent studies on vibrationally highly excited acetylene. A convolution analysis, one type of hierarchical analysis, is performed on the dispersed fluorescence spectrum of acetylene to demonstrate its practical applicability. Based on previous studies, as well as on the convolution analysis, a systematic and efficient procedure to treat such complex spectra is discussed.