The Spectra of K III, Ca IV, and Sc V, and their Relation to the Spectra of Other Ions in the Isoelectronic Sequence Cl I to Mn IX

The successful excitation of highly ionized scandium atoms has enabled the classification of Sc V multiplets which arise from transitions between 3s²3p⁵²P⁰ and 3s3p⁶ ²S; 3s²3p⁴4s 4, 2P, ²D, ²S. Spectrograms of scandium and calcium have been taken with a twenty-one foot grazing incidence vacuum spectrograph. The large dispersion and resolution of this instrument enabled the above transitions to be identified in Ca IV also. The identification of these multiplets supplies spectroscopic data necessary to complete the study of the isoelectronic regularities in the sequence.