Electronic stopping of protons for lithium in the dielectric formulation obtained from first-principles calculations

We calculate the wave-vector and frequency-dependent dielectric matrix of b ulk crystals by use of first-principles, all-electron Kohn-Sham states in t he integral of the irreducible polarizability in the random phase approxima tion. From this we determine the macroscopic "head" element, the (0, 0)-ele ment, of the inverse matrix (the energy loss function), and integrate over energy and momentum transfers to obtain the electronic energy loss of proto ns at low velocities. Numerical results are given for hexagonal close packe d lithium. (C) 1999 Published by Elsevier Science B.V. All rights reserved.