108 research outputs found
Relativistic corrections of m\alpha^6 order to the ro-vibrational spectrum of H_2^+ and HD^+ molecular ions
The major goal of the high-precision studies of ro-vibrational states in the
hydrogen molecular ions is to provide an alternative way for improving the
electron-to-proton mass ratio, or the atomic mass of electron. By now the
complete set of relativistic and radiative corrections have been obtained for a
wide range of ro-vibrational states of H_2^+ and HD^+ up to order
R_\infty\alpha^4. In this work we complete calculations of various
contributions to the R_\infty\alpha^4 order by computing the relativistic
corrections to the binding energy of electron.Comment: 4 pages, 1 figur
Proposed method for laser spectroscopy of pionic helium atoms to determine the charged-pion mass
Metastable pionic helium () is a three-body atom composed of a
helium nucleus, an electron occupying the ground state, and a negatively
charged pion in a Rydberg state with principal- and orbital angular
momentum quantum numbers of . We calculate the
spin-independent energies of the and
isotopes in the region --19. These include relativistic and quantum
electrodynamics corrections of orders and
in atomic units, where and denote
the Rydberg and fine structure constants. The fine-structure splitting due to
the coupling between the electron spin and the orbital angular momentum of the
, and the radiative and Auger decay rates of the states are also
calculated. Some states and retain
nanosecond-scale lifetimes against absorption into the helium nucleus.
We propose to use laser pulses to induce transitions from these
metastable states, to states with large ( s) Auger rates.
The ion that remains after Auger emission of the
electron undergoes Stark mixing with the , , and states during
collisions with the helium atoms in the experimental target. This leads to
immediate nuclear absorption of the . The resonance condition between
the laser beam and the atom is thus revealed as a sharp spike in the rates of
neutrons, protons, deuterons, and tritons that emerge....(continued)Comment: 25 pages, 3 tables, 11 figure
Calculation of the relativistic Bethe logarithm in the two-center problem
We present a variational approach to evaluate relativistic corrections of
order \alpha^2 to the Bethe logarithm for the ground electronic state of the
Coulomb two center problem. That allows to estimate the radiative contribution
at m\alpha^7 order in molecular-like three-body systems such as hydrogen
molecular ions H_2^+ and HD^+, or antiprotonic helium atoms. While we get 10
significant digits for the nonrelativistic Bethe logarithm, calculation of the
relativistic corrections is much more involved especially for small values of
bond length R. We were able to achieve a level of 3-4 significant digits
starting from R=0.2 bohr, that will allow to reach 10^{-10} relative
uncertainty on transition frequencies.Comment: 19 pages, 5 tables, 7 figure
Hunting for Homo Sovieticus: Situational versus Attitudinal Factors in Economic Behavior
macroeconomics, Soviet Union, attitudinal, situational, economic behavior, Russia
Hydrogen molecular ions for improved determination of fundamental constants
The possible use of high-resolution rovibrational spectroscopy of the
hydrogen molecular ions H + 2 and HD + for an independent determination of
several fundamental constants is analyzed. While these molecules had been
proposed for metrology of nuclear-to-electron mass ratios, we show that they
are also sensitive to the radii of the proton and deuteron and to the Rydberg
constant at the level of the current discrepancies colloquially known as the
proton size puzzle. The required level of accuracy, in the 10 --12 range, can
be reached both by experiments, using Doppler-free two-photon spectroscopy
schemes, and by theoretical predictions. It is shown how the measurement of
several well-chosen rovibrational transitions may shed new light on the
proton-radius puzzle, provide an alternative accurate determination of the
Rydberg constant, and yield new values of the proton-to-electron and
deuteron-to-proton mass ratios with one order of magnitude higher precision
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