New values for some /sup 4/He I 1snl energy levels, ionization energies, and Lamb shifts

Journal Article · Sun Apr 01 04:00:00 EST 1984 · Phys. Rev. A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.29.1883· OSTI ID:7051370

Martin, W C

Recent experimental determinations of energy separations within the 1snl term system (n = 2--6) have been used to reevaluate 35 levels. Most of the levels have estimated errors less than 0.001 cm/sup -1/ relative to the 2 /sup 3/P levels. Addition of accurate theoretical term values (ionization energies) available for several 1snl levels to the corresponding experimental level values gives generally consistent values for the principal ionization energy (E/sub I/). The theoretical energies are further confirmed by the agreement of the weighted average of seven of these E/sub I/ values with a value obtained by fitting Ritz formulas to three accurately determined 1snl series; the suggested new E/sub I/ is 198 310.7745(40) cm/sup -1/ on an energy scale fixed by the value 171 135.0000 cm/sup -1/ for 2 /sup 1/P. Lamb shifts are derived for the 2, 3, 4 /sup 3/S/sub 1/, 2 /sup 1/S/sub 0/, 2 /sup 3/P/sub 1/, and 2/sup 1/P/sub 1/ levels as differences between experimental term values obtained with the new E/sub I/ and corresponding calculated term values not including Lamb shifts. The experimental and calculated values for the 1s/sup 2/ /sup 1/S/sub 0/ ground level relative to the present 1snl excited-level system are 0.00 +- 0.15 and 0.073 +- 0.009 cm/sup -1/, respectively, so that a approx.20-fold increase in the experimental accuracy would be required to test the calculated ground-level Lamb shift.

• Research Organization: National Measurement Laboratory, National Bureau of Standards, Washington, DC 20234
• OSTI ID: 7051370
• Journal Information: Phys. Rev. A; (United States), Journal Name: Phys. Rev. A; (United States) Vol. 29:4; ISSN PLRAA
• Country of Publication: United States
• Language: English

Related Subjects

640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
ACCURACY
COMPARATIVE EVALUATIONS
DATA
ENERGY LEVELS
EVEN-EVEN NUCLEI
EXPERIMENTAL DATA
HELIUM 4
HELIUM ISOTOPES
INFORMATION
IONIZATION POTENTIAL
ISOTOPES
LAMB SHIFT
LIGHT NUCLEI
NUCLEI
NUMERICAL DATA
SPECTRAL SHIFT
STABLE ISOTOPES