Calculations of Superconducting Properties in Yttrium and Calcium under High Pressure*

We have used first-principles electronic structure calculations to generate the bulk modulus as a function of volume as well as the densities of states and scattering phase shifts at the Fermi level. These quantities were used in conjunction with the rigid-muffin-tin theory of Gaspari and Gyorffy and the McMillan theory to determine the electron-phonon coupling and the superconducting transition temperature for Yttrium and Calcium under high pressures. Our results provide a good interpretation of the measured increase of $T_{c}$ in these metals.