Vacuum-Ultraviolet Series of Mg i and Mg ii*

Ten members of the principal series of Mg i (3s2 1S0–3snp1P1°, n = 3–n = 12) have been observed and measured in emission. This is the first observation in emission for the members (n = 5–n = 12) in the vuv. The present observations are compared with the predicted values and with measurements in absorption. A quantum-defect plot is presented. The wavelengths of 34 Mg ii lines have been measured in the spectral range from 946 to 2937 Å. These Mg ii lines belong to the principal series (3s2S–np2P°), the diffuse series (3p2P°–nd2D), and the sharp series (3p2P°–ns2S). Nineteen of the Mg ii lines reported in the vuv have not been measured previously.