Infrared reflectivity and Raman scattering of lithium oxide single crystals

Infrared reflection and Raman spectra of single crystals of lithium oxide have been measured at room temperature. The reflection spectra have been analyzed by means of a fit with a classical dispersion formula. The result gives the frequencies of the fundamental transverse and longitudinal optical modes as 425 and 737 cm^?1, respectively. The frequency of the Raman active fundamental mode is also established at 523 cm^?1. From these frequencies an effective charge of lithium ion and effective force constants are obtained on the basis of lattice dynamical models.