  Tantalum diselenide (TaSe$_{2}$) is a metallic transition metal
dichalcogenide whose equilibrium structure and vibrational behavior strongly
depends on temperature and thickness, including the emergence of charge density
wave (CDW) states at very low T. In this work, observed modes for mono- and
bi-layer are described across several spectral regions and com-pared to the
bulk ones. Such modes, including an experimentally observed forbidden Raman
mode and low frequency CDW modes, are then matched to corresponding density
functional theory (DFT) predicted vibrations, to unveil their inner working.
The excellent match between experimental and computational results justifies
the presented vibrational visualizations of these modes. Additional support is
provided by experimental phonons seen in Raman spectra as a function of
temperature and thickness. These results highlight the importance of
understanding interlayer interactions and their effects on mode behaviors.
