Third Spectrum of Palladium (Pd III).

The Pd III spectrum has been observed from 688 to 2991 A, and the earlier analysis has been revised and extended. The number of Pd III lines here reported is 1,110, of which 917 are classified as combinations of 57 even energy levels with 111 of odd parity. The interpretation has been aided by theoretical predictions of the approximate positions of expected energy levels. Spectral terms from the 4d 8, 4d 7 ns 1, and 4d 6 5s 1 5p 1 configurations are designated. Eight limit terms are in the 4d 7 ns 1 configurations. The earlier ionization potential, 33.0 electron volts derived from the (ns 1) 3,5 F series (n=5,6) by means of a Ritz formula, remains unchanged.