ENERGY-LOSS AND STRAGGLING OF HEAVY-IONS IN CONDENSED MATTER

The stopping power and energy straggling of energetic projectiles passing through matter can be split into a collisional term and a contribution from the charge exchange process. To properly describe the stopping power and straggling of heavy projectiles in condensed matter, partial effective charges (PECs) are introduced to describe the charge-state-dependent stopping power and straggling in a charge state model. A new formula for the partial straggling effective charge (PSGEC) has been derived while the partial stopping effective charge (PSPEC) has been formulated in the Brandt-Kitagawa (BK) model. With the related PECs, the partial stopping power and straggling of singly charged projectiles can be obtained by scaling to those of bare nucleus. The collisional stopping power and straggling are contributed from all charge states weighted by their equilibrium charge fraction. The charge exchange contribution can be calculated with knowledge of charge exchange cross sections. The stopping power and straggling of swift C ions in carbon have been calculated and compared with empirical results as well as recent experiments.