Surface segregation energies in transition-metal alloys

We present a database of 24 x 24 surface segregation energies of single tra nsition metal impurities in transition-metal hosts obtained by a Green's-fu nction linear-muffin-tin-orbitals method in conjunction with the coherent p otential and atomic sphere approximations including a multipole correction to the electrostatic potential and energy. We use the database to establish the major factors which govern surface segregation in transition metal all oys. We find that the calculated trends are well described by Friedel's rec tangular state density model and that the few but significant deviations fr om the simple trends are caused by crystal structure effects. [S0163-1829(9 9)05424-7].