4d-photoabsorption of Ba, Ba/sup +/, and Ba/sup + +/: a view of shell collapse vs. contraction

Conference · Fri Jan 01 04:00:00 EST 1982 · AIP Conf. Proc.; (United States)

OSTI ID:5732383

Lucatorto, T B; McIlrath, T J; Hill, III, W T; Clark, C W

Ba with Z=56 is at the edge of 4f collapse; neutral ground state atoms with Z<56 have 4f orbitals which are hydrogenic with r/sub av/approx.17a/sub 0/ while elements with Z>56 have a collapsed 4f orbital with r/sub av/approx.1a/sub 0/. Since the 4d orbital is collapsed (r/sub av/approx.1a/sub 0/) the nature of the 4d-absorption is expected to depend critically on whether the 4f orbital can be considered collapsed or not. Using a laser technique to prepare dense homogeneous columns of Ba/sup +/ and Ba/sup + +/ the 4d photoabsorption spectra of Ba, Ba/sup +/ and Ba/sup + +/ have been obtained. This technique thus allows the authors to observe the effects on the 4f orbitals of the increased nuclear attraction experienced in the absence of screening by the 6s electrons. It is found that exchange effects are critically important in configurations of the type 4d/sup 9/4f, and that progressive contraction rather than collapse is a more appropriate description under such conditions. 23 references, 14 figures, 1 table.

• Research Organization: National Bureau of Standards, Washington, DC
• OSTI ID: 5732383
• Report Number(s): CONF-820855-
• Conference Information: Journal Name: AIP Conf. Proc.; (United States) Journal Volume: 94
• Country of Publication: United States
• Language: English

Related Subjects

640302* -- Atomic
Molecular &amp; Chemical Physics-- Atomic &amp; Molecular Properties &amp; Theory
74 ATOMIC AND MOLECULAR PHYSICS
ABSORPTION SPECTRA
ALKALINE EARTH METALS
BARIUM
BARIUM IONS
CATIONS
CHARGED PARTICLES
ELECTRONIC STRUCTURE
ELEMENTS
ENERGY-LEVEL TRANSITIONS
FUNCTIONS
IONS
MATHEMATICAL MODELS
METALS
OSCILLATOR STRENGTHS
QUANTUM NUMBERS
SPECTRA
WAVE FUNCTIONS