Contributions of thermal charge exchange excitation to the Rydberg series of Cl16+

Spectra from the Rydberg series 1s-np for the principal quantum numbers n g reater than or equal to 8 of Cl16+ are observed on the JET tokamak. Individ ual lines up to n = 15 are resolved. The line intensity of n = 10 is enhanc ed, relative to the underlying 1/n(3) scaling, due to charge exchange colli sions with neutral deuterium in the ground state. The observations are comp ared with predictions based on available partial charge exchange cross sect ion data. There is generally good agreement, however, some details of the p redicted n-shell distribution are different from those observed in the expe riment.