The Excitation of Forbidden Spectral Lines

From Majorana Theory of Atomic Autoionization to Feshbach Resonances in High Temperature Superconductors

“…3. The two electrons excitations in the optical absorption spectra of Cd measured by Foote et al (1925) [21].…”

“…These two electron excitations were measured as week absorption lines in the atomic spectra beyond the ionization potential (I.P.) for single electron excitations [21][22][23]. The optical absorption spectrum of Cd, measured by Foote et al in 1925 [21] is shown in Fig.…”

“…These two electron excitations were measured as week absorption lines in the atomic spectra beyond the ionization potential (I.P.) for single electron excitations [21][22][23] Majorana has shown in his work [2] that the expected final states are…”

Magnetic Multipole Transition Probabilities

“…in samples of cadmium with enriched odd isotope abundances that magnetic quadrupole radiation is indeed present (see Garstang, 1967). The Zni line at 13040 was observed by Fukuda (1926) and Foote et al (1925); they deserve the credit for being the first to observe a magnetic quadrupole line in the laboratory. The Mgi line at 14562.5 was observed by Bowen (1960) in the planetary nebula NGC 7027.…”

From the Majorana theory of "Incomplete P' triplets" to Feshbach resonances

“…3. The two electrons excitations in the optical absorption spectra of Cd measured by Foote et al (1925) [25].…”