Theoretical studies of core-excited states of two- and three-electron atoms
We have carried out configuration-interaction calculations for /sup 4/F/sup e/,o states of Li and Be = and for the lowest /sup 4/D/sup e/,o states of Be/sup +/ in an effort to test the accuracy that can be achieved in transition-energy calculations by assuming transferability of relativistic, radiative, and mass-polarization corrections among similar electron cores. He and Li/sup +/ 2p4f /sup 1/ /sup 3/F states have also been considered. The nonrelativistic result for the Li 1s2p4f /sup 4/F..-->..1s2s4f /sup 4/F/sup 0/ transition is lambda/sub air/ = 5474.3 +- 0.4 A. Including relativistic, radiative, and mass-polarization corrections for the 1s2p /sup 3/P and 1s2s /sup 3/S Li/sup +/ cores we get lambda = 5471.7 +- 0.4 A, in excellent agreement with a lambda = 5471.9 +- 1.4 A recently observed in the beam-foil source. Stronger support for our basic assumption comes from three calculated (experimental) wavelengths lambda = 3406.0 +- 0.3(3405.6 +- 0.6), 4330.1 +- 0.5(4330.2 +- 0.5), and 3510.8 +- 0.5(3510.8 +- 0.5) A in the Be II** spectrum. Furthermore, three lines (the first two above and lambda = 981 A) have been reassigned and three new wavelengths are predicted for this spectrum. The 1s2s4f +- 1s2p3d nature of the /sup 4/F/sup o/(1) and /sup 4/F/sup o/(2) states in Be/sup +/ is responsible for the uncommon situation that /sup 4/F/sup o/(1) is below 1s2s4d /sup 4/D/sup o/(2), thus explaining the failure of some of the earlier assignments. The lowest Be/sup +/ 1s2s2p /sup 4/P/sup o/ state is found 115.845 +- 0.016 eV above the Be/sup +/ 1s/sup 2/2s ground state, in fair agreement with a recent experimental value of 115.7 +- 0.1 eV. The He and Li/sup +/ 2p4f /sup 1,3/F states decay to 1s4f /sup 1,3/F states with wavelengths too close to the resonance transition 2p ..-->.. 1s of the corresponding one-electron system to be observed in beam-foil experiments. The Li/sup +/ 2p4f /sup 1,3/F states, however, decay to 2p3d /sup 1,3/D states with lambda = 3825.4 +- 0.1 and 4352.2 +- 0.1 A, respectively, and they should be susceptible of experimental observation.
- Research Organization:
- Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Apartado 20-364, Mexico 20, D.F., Mexico
- OSTI ID:
- 6562531
- Journal Information:
- Phys. Rev., A; (United States), Vol. 23:4
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BERYLLIUM IONS
CONFIGURATION INTERACTION
D STATES
ENERGY-LEVEL TRANSITIONS
F STATES
HELIUM
LITHIUM
ALKALI METALS
CHARGED PARTICLES
ELEMENTS
ENERGY LEVELS
FLUIDS
GASES
IONS
METALS
NONMETALS
RARE GASES
640302* - Atomic
Molecular & Chemical Physics- Atomic & Molecular Properties & Theory