The room-temperature elastic moduli $c_{\mathrm{ij}}$ of AgGa${\mathrm{S}}_2$ have been determined using laser Brillouin scattering. This is the first determination of these moduli for any of the ternary compounds which crystallize with the chalcopyrite structure. From the Brillouin shifts the following values for the elastic moduli were obtained: $c_{11}=8.79\mathrm{}\pm 0.05$, $c_{33}=7.58\mathrm{}\pm 0.05$, $c_{44}=2.41\mathrm{}\pm 0.05$, $c_{66}=3.08\mathrm{}\pm 0.05$, $c_{12}=5.84\mathrm{}\pm 0.05$, and $c_{13}=5.92\mathrm{}\pm 0.06$, in units of ${10}^{11}$ dyn/${\mathrm{cm}}^2$.

• Received 14 July 1975

DOI:https://doi.org/10.1103/PhysRevB.12.4377