High-resolution uv laser spectroscopy of the 1s2s /sup 3/S/sub 1/. -->. 1snp (n = 5--79) transitions in /sup 3/He and /sup 4/He

Journal Article · Mon May 01 04:00:00 EDT 1989 · Phys. Rev. A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.39.4615· OSTI ID:6068178

Vassen, W; Hogervorst, W

The /sup 4/He fine structure and /sup 3/He hyperfine structure as well as the isotope shift between /sup 4/He and /sup 3/He in the 1s2s /sup 3/S/sub 1/..-->..1snp (n = 5--79) transitions have been measured using an atomic beam and an intracavity frequency-doubled coumarin ring dye laser near 270 nm. The observed 1snp /sup 3/P /sup 4/He fine structure is in agreement with (extrapolations of) existing experimental results and theoretical calculations. The 1snp /sup 3/He hyperfine structure has been analyzed using the /sup 4/He fine-structure parametrization and the Fermi-contact interaction of the screened 1s electron. For n>35 hyperfine components of the 1snp /sup 1/P levels are also excited as a consequence of hyperfine-induced singlet-triplet mixing. Calculated hyperfine splittings agree with experiment for n<20. Deviations up to 50 MHz are observed for n>20. These are shown to be due to hyperfine-induced n-mixing effects. The experimental results are excellently reproduced in a three-channel two-limit quantum-defect model without any adjustable parameter. The observed 1s2s /sup 3/S/sub 1/..-->..1snp /sup 3/P isotope shifts can be fully explained using recent mass polarization calculations for the 1s2s /sup 3/S/sub 1/ and 1snp (n = 3--8) /sup 3/P levels and confirm an isotope dependence of

for the 1s2s /sup 3/S/sub 1/ level.

• Research Organization: Faculteit Natuurkunde en Sterrenkunde, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
• OSTI ID: 6068178
• Journal Information: Phys. Rev. A; (United States), Journal Name: Phys. Rev. A; (United States) Vol. 39:9; ISSN PLRAA
• 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
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
EXCITED STATES
FINE STRUCTURE
HELIUM 3
HELIUM 4
HELIUM ISOTOPES
HYPERFINE STRUCTURE
ISOTOPE EFFECTS
ISOTOPES
LASER SPECTROSCOPY
LIGHT NUCLEI
NUCLEI
RYDBERG STATES
SPECTRAL SHIFT
SPECTROSCOPY
STABLE ISOTOPES