Acetylacetone, double‐deuterated acetylacetone and hexafluoroacetylacetone were isolated in inert matrices and investigated by means of Raman scattering and infrared absorption spectroscopic methods, combined with theoretical calculations. The ability of Raman spectroscopy to access low wavenumber modes enables the study of vibrational modes involved in internal hydrogen bonds that are challenging to observe with infrared absorption spectroscopy. An almost complete set of vibrational modes for the studied molecules was observed experimentally, facilitating a comprehensive assessment of different computational approaches. The large dataset obtained allowed for an improved assignment of vibrational bands and firmly confirmed the existence of only one chelated isomer of acetylacetone, double‐deuterated acetylacetone and hexafluoroacetylacetone in matrices. The experimental data also highlighted the effects of deuteration and fluorination.