Calculated elastic constants and structural properties of Mo and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">MoSi</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

Using an all-electron, self-consistent, full-potential, linear muffin-tin-orbitals method within the local-density approximation of density-functional theory, we have studied the structural properties and the elastic constants of Mo and ${\mathrm{MoSi}}_{2}$. The Mo and ${\mathrm{MoSi}}_{2}$ ground-state properties, lattice parameters, cohesive energy, and (for Mo) elastic constants are found to be in good agreement with the experimental results. Different structures in the angle-integrated photoemission spectrum of ${\mathrm{MoSi}}_{2}$ can be satisfactorily explained in terms of various features present in the calculated total density of states. Since there have been no previous theoretical or experimental determinations, our calculations provide the first available information on the elastic constants of ${\mathrm{MoSi}}_{2}$. For both Mo and ${\mathrm{MoSi}}_{2}$ we have calculated the stress tensors for the experimental structures and have minimized their elastic energies. We have found that the lattice parameters and the ground-state total energies of Mo and ${\mathrm{MoSi}}_{2}$ obtained from both the elastic energy and the total-energy minimizations are about the same, and that the lattice parameters are close to their experimental values.