268 research outputs found
Relativistic energy shifts in Ge II, Sn II and Pb II and search for cosmological variation of the fine structure constant
Sensitivity of atomic transition frequencies to variation of the fine
structure constant increases proportional to where
is the nuclear charge. Recently several lines of heavy ions Ge II, Sn II
and Pb II have been detected in quasar absorption spectra. We have performed
accurate many-body calculations of -dependence of transition
frequencies (-coefficients) for these atoms and found an order of magnitude
increase in sensitivity in comparison with atomic transitions which were
previously used to search for temporal and spatial variation of in
quasar absorption systems. An interesting feature in Pb II is highly non-linear
dependence on due to the level pseudo-crossings.Comment: 5 pages, 3 tables, 1 figure, submitted to Phys. Rev.
Ion clock and search for the variation of the fine structure constant using optical transitions in Nd and Sm
We study ultranarrow - transitions in Nd and
Sm and demonstrate that they lie in the optical region. The transitions
are insensitive to external perturbations. At the same time they are sensitive
to the variation of the fine structure constant . The fractional
accuracy of the frequency of the transitions can be smaller than ,
which may provide a basis for atomic clocks of superb accuracy. Sensitivity to
the variation of approaches per year.Comment: 4 pages, 2 tables, no figure
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