Energy and Width Measurements of Low-ZPionic X-Ray Transitions

New measurements have been performed of the energies and natural linewidths of $2p-1s$ pionic x-ray transitions, as well as muonic transition energies, in ${\mathrm{Li}}^6$, ${\mathrm{Li}}^7$, ${\mathrm{Be}}^9$, ${\mathrm{B}}^{10}$, ${\mathrm{B}}^{11}$, and ${\mathrm{C}}^{12}$. High-resolution Si(Li) and Ge(Li) spectrometers were used, resulting in a more precise determination than those previously reported of the transition energies and natural linewidths. Comparison of the measured complex energy shifts in the pionic transitions has been made with the theory of the Ericsons and good agreement found.