Excitation ofC3+by electron impact

Abstract

The $2s-2p$ transition in the lithiumlike ion ${\mathrm{C}}^{3+}$ is studied in the resonance region below the $n=3\mathrm{}$ threshold. A five-state close-coupling expansion is used. Cross sections are calculated using the $R$-matrix method for $\mathrm{O}\le L\le 4$ and the noniterative integral-equation method for $L>\mathrm{}4\mathrm{}$. A complicated structure of numerous, generally narrow, resonances is obtained for impact energies in the range 1.4-2.6 Ry. The resonances lead to a small overall enhancement of the average cross section.