  Interest in the bulk transition metal dichalcogenides for their electronic,
photovoltaic, and optical properties has grown and led to their use in many
technological applications. We present a systematic investigation of their
interlinked vibrational and dielectric properties, using density functional
theory and density functional perturbation theory, studying the effects of the
spin-orbit interaction and of the long-range e$^-$- e$^-$ correlation as part
of our investigation. This study confirms that the spin-orbit interaction plays
a small role in these physical properties, while the direct contribution of
dispersion corrections is of crucial importance in the description of the
interatomic force constants. Here, our analysis of the structural and
vibrational properties, including the Raman spectra, compare well to
experimental measurement. Three materials with different point groups are
showcased and data trends on the full set of fifteen existing hexagonal,
trigonal, and triclinic materials are demonstrated. This overall picture will
enable the modeling of devices composed of these materials for novel
applications.
