EXCITATION OF ATOMIC-HYDROGEN BY PROTONS AND MULTIPLY-CHARGED IONS ATINTERMEDIATE VELOCITIES

We have investigated the collisional excitation of hydrogen atoms by p rotons and multiply charged ions at intermediate velocities applying t he optical method. The population of the np levels (n=2,..., 6) has be en determined for a variety of projectiles with charge states q rangin g from 1+ to 11+ and scaled velocities v/root q between 0.7 and 5.6 au . The cross sections are shown to fulfil the scaling relation sigma/q= f(v(2)/q) with respect to the projectile charge q and velocity v for q greater than or equal to 3. The relevance of scaled intermediate velo cities for a classification of excitation mechanism is pointed out.