Cao and Chen investigated the lattice anharmonicity as a function of temperature using the Raman spectroscopy, a "tool which can directly provide a great deal of information about the optical phonon near the center of the Brillouin zone". Information is coming from the peak frequency and FWHM (full width at half maximum). Cao and Chen note that anharmonicity has been widely investigated on silicon and other 2D-materials by means of the temperature dependence of the Raman spectra, but for 2H-MoS2, it "was reported sparsely". Cao and Chen used a synthetic sample, collecting the Raman spectra "with a laser power down to 1.0 mw to avoid laser the heating effect. The heating effects are quantified by the ratio of the anti-Stokes to Stoke Raman intensity at room temperature and found to be 3-12 K". The phonon modes in 2H-MoS2 are A1g + 2B2g + E1g + 2E2g + 2A2u + B1u + 2E1u + E2u. The Raman active modes are A1g, E1g, E 1 2g, and E 2 2g. Let us note the presence of B1u mode; we will find it in our Section about Davydov splitting. "In TMDs, the E1g mode is always weak due to its small scattering cross section" (Cao and Chen, mentioning . The commonly observed Raman peaks are at (cm -1 ): 34.7 (E 2 2g), 385.6 (E 1 2g), 410.9 (A1g). The spectra at room temperature proposed by Cao and Chen agree "very well with previous publications" (Cao and Chen, mentioning .