In Na et al., 2018, we can find a discussion about the "Davydov splitting and polytypism in few-layer MoS2". In Molybdenum disulfide, "although the interaction between the layers is the weak van der Waals interaction, its influence on the physical properties is significant" . The interlayer interaction is influencing the band structure, so its study is relevant, especially as depending on the number of layers. "The interlayer interaction manifests itself in the form of Davydov splitting, which in the case of vibrational modes is a splitting of the degenerate normal modes due to a weak interaction between the oscillators" . "In the case of transition metal dichalcogenides (TMDs), Davydov splitting appears … and has been observed" in WS2, MoTe2, MoSe2, and WSe2 (Na et al., and references therein). In the case of MoS2, "there is a complication because even natural MoS2 crystals show polytypism … Since the interlayer interaction would depend on the stacking types, finding the correlation between the stacking types and the interlayer interaction is an important issue for correct characterization of the physical properties" .