Abstract
Raman scattering and infrared reflectance have been measured in 2H-MoSe2. We observed all Raman-active modes, A1g, E1g, E2g1 and E2g2, and two infrared-active modes, E1u2 and A2u2. Intralayer force constants are estimated from the central force model. The bond between metal (Mo) and chalcogen (Se) predominates over the high-lying phonon frequencies with long wavelength. On the other hand, interlayer shear force constant is estimated from the frequency of E2g2 mode, that is a rigid-layer mode, and is much smaller than the intralayer force constants. This fact, which is similar to that in other group VIB transition-metal dichalcogenides, reflects that the interlayer interaction is due to van der Waals force. The second-order Raman spectrum has been also observed and discussed.
