Table 3. Zone centre vibrational frequencies ν (cm⁻¹) of the bulk (MoS₂-2H), monolayer (MoS₂-1L) and bilayer (MoS₂-2L) models, as obtained from PBE-D3 simulations, compared with experimental results (Exp.) where these are available.

Activity in infrared and/or Raman spectroscopy is indicated with IR or R, respectively.

System	Mode	Irrep a	ν a	IR/R	Exp. b	Exp. c	VFF d	PW91+D e
MoS2-2H	1	E 1u	0.0
	2	A 2u	0.0
	3	E 2g	36.0	R		32
	4	B 1g	62.4	R
	5	E 2u	282.1	IR				285.0
	6	E 1g	285.3	R		287		286.6
	7	E 2g	381.0	R	383.5	383		378.5
	8	E 1u	381.3	IR				378.8
	9	B 2u	402.5	IR				395.4
	10	A 1g	411.7	R	408.9	409		400.2
	11	A 2u	464.5	IR				456.9
	12	B 1g	470.1	R				460.3
MoS2-1L	1		0.0
	2	E′	0.0
	3	E′′	281.9	R			280	287.1
	4	E′	381.8	IR, R	384.4		384	380.2
	5		402.3	R	403.1		407	406.1
	6		467.7	IR			481	465.0
MoS2-2L	1	E u	0.0
	2	A 2u	0.0
	3	E g	24.8	R
	4	A 1g	42.6	R
	5	E u	281.9	IR
	6	E g	283.5	R
	7	E g	381.3	R	383.9
	8	E u	381.4	IR
	9	A 2u	402.3	IR
	10	A 1g	406.5	R	404.6
	11	A 2u	466.8	IR
	12	A 1g	468.8	R

References: (a) present work, (b) Funke et al. (2016 ▸), (c) Wieting & Verble (1971 ▸), (d) Jiménez Sandoval et al. (1991 ▸) using the valence force field (VFF) model and (e) Ataca et al. (2011 ▸) using the DFT/PW91-D approach.