Photoabsorption of the 4d electrons in barium

Publisher Website
Google Scholar
Abstract
The absorption spectrum of gaseous barium was obtained between 120 AA and 140 AA, the region of the NIV,V thresholds. The similarity to lanthanum of some of the features observed in barium suggests that the 4f orbital contracts and overlaps the 4d orbit. This contraction produces two terms, 3P and 3D, of the 4d94f configuration below the 4d ionization limits, while the large electrostatic exchange interaction drives the 1P term of this configuration some 10 eV above the limit. Furthermore, extensive mixing of the 4d9(6s2)6p configuration with 4d9(5d2)6p and 4d9(5d6s)6p produces many weak resonances in addition to the resonances associated with the 4d94f configuration. A suggested classification of these features is given with the aid of known features of the La I spectrum. Finally, from the known X-ray splitting of the NIV,V threshold and the energy interval between the 6s26p 2P and 6s2 1S levels in La I and La II, the ionization thresholds of the 4d electron were determined to be 814800 (1000) cm-1 and 792500 (1000) cm-1.

This publication has 15 references indexed in Scilit: