LONG WAVELENGTH OPTIC PHONONS IN WSE2

The first order Raman spectrum of the layer type semiconducting compound, WSe//2, has been investigated. The frequencies of the Raman active A//1//g, E//2//g**1, E//1//g, and E//2//g**2 modes have been compared to the values obtained previously for the isostructural compound 2H-MoS//2. The good agreement that is obtained between the measured and calculated values is taken as corroboration of the present assignments in WSe//2.