On the ground configuration of the phosphorus sequence from copper to molybdenum

The energy-level structure of the 3s23p3 configuration of the phosphorus sequence ions Mo xxviii and Zr xxvi has been determined from magnetic-dipole line wavelengths and emissivities measured in the Princeton Large Torus tokamak discharges. The new measurements have caused some changes in the tentative assignments reported earlier for this sequence, especially for the 4S3/2–2D3/2 transitions. Isoelectronic interpolations together with some experimental confirmations in the Se xx and Ge xviii spectra now permit a reasonably accurate and complete reconstruction of this configuration from Z = 42 to previously established Z ≤ 28 elements. The measured wavelengths and relative intensities are in substantial agreement with recent semiempirical evaluations and ab initio calculations.