Absorption spectra of Zn i and Cd i in the 1300–1750 Å region

The high-dispersion absorption spectra of Zn i and Cd i have been photographed in the ~1300–1750 Å region. Observations include the principal-series transitions ms2 S1-msnp P11°, the electric-quadrupole transitions ms2 1S–msnd1D2, and the intercombination transitions ms2 S1-msnp P31° (m = 4 and 5 for zinc and cadmium, respectively). Energy levels are presented for msnp P11° (m<n≤66), msnp1D2 (m = 4 < n ≤ 20 for Zn i and m = 5 < n ≤ 26 for Cd i) and msnp P31° (m = 4 < n ≤ 12 for Zn i and m = 5 < n ≤ 31 for Cd i). The ionization potentials of Zn i and Cd i determined from the msnp P11° series are 75769.33 ± 0.18 cm−1 and 72540.07 ± 0.18 cm−1, respectively. At high metal-vapor pressures in the presence of argon, diffuse satellite lines appeared with the strong atomic transitions.