exchange-correlation and continuum pressure effects with using the effective
functionals [37, 65, 66].
The difference between the obtained theoretical data and other alternative calculation results can be explained by using different perturbation theory schemes and
different approximations for calculating the electron wave functions of heavy
atoms. It is obvious that the correct account for the relativistic and exchangecorrelation and continuum pressure effects will be necessary for an adequate
description of the energetic and spectral properties of the heavy atoms in an
atmosphere of the heavy inert gases (for example, such as Xe).
5 Conclusion
In this chapter a brief review of the experimental and theoretical works on the
hyperfine structure line collision shifts for heavy atoms in an atmosphere of the
buffer inert gases is given. A new, consistent relativistic perturbation theory combined with the exchange perturbation theory, is presented and applied to calculating
the interatomic potentials, van der Waals constants, hyperfine line collision shift
and broadening for some heavy atoms in an atmosphere of the buffer inert gases. It
should be noted that the presented approach can be naturally generalized in order to
describe the energy and spectral characteristics of other atomic systems and buffer
mediums.
The calculation results on the hyperfine line collision shift and broadening for
the alkali (Rb, Cs), thallium, and ytterbium atoms in an atmosphere of the inert gas
(He, Kr, Xe) are listed and compared with available alternative theoretical and
experimental results. The obtained data for the (Г a /p)/f p ratio allowed to confirm
that the well-known Foley law Г a * f p in the theory of optical range spectral line
broadening is incorrect for the spectral lines of transitions between components of
the hyperfine structure of the heavy multielectron atoms.
The studying hyperfine structure line collision shifts and widths for different
heavy atomic systems in the buffer gases opens new prospects in the bridging of
quantum chemistry and atomic and molecular spectroscopy and physics of collisions. These possibilities are significantly strengthened by a modern experimental
laser and other technologies [22–24, 98–106]. Really, new experimental technologies in physics of collisions may provide a measurement of the atomic and
molecular collision spectral parameters with very high accuracy.
Acknowledgments The support of the Odessa State University—OSENU as well as of the
Ministry of Education and Science of Ukraine (2013) is acknowledged. The author would like to
thank Prof. Marco Nascimento for his invitation to present this contribution at QSCP-XVIII
(Paraty, Rio de Janeiro, Brazil), and Prof. Andrey N. Starostin (Centre for Theoretical Physics and
Computational Mathematics, Research State Center of the Russian Federation “Troitsk Institute for
Innovation and Fusion Research”, Troitsk, Russian Federation) and Vladimir G. Shevchuk
(Department of Chemical Physics, Odessa National University, Odessa, Ukraine) for useful
comments.
Optimized Perturbation Theory for Calculating the Hyperfine …
73
functionals [37, 65, 66].
The difference between the obtained theoretical data and other alternative calculation results can be explained by using different perturbation theory schemes and
different approximations for calculating the electron wave functions of heavy
atoms. It is obvious that the correct account for the relativistic and exchangecorrelation and continuum pressure effects will be necessary for an adequate
description of the energetic and spectral properties of the heavy atoms in an
atmosphere of the heavy inert gases (for example, such as Xe).
5 Conclusion
In this chapter a brief review of the experimental and theoretical works on the
hyperfine structure line collision shifts for heavy atoms in an atmosphere of the
buffer inert gases is given. A new, consistent relativistic perturbation theory combined with the exchange perturbation theory, is presented and applied to calculating
the interatomic potentials, van der Waals constants, hyperfine line collision shift
and broadening for some heavy atoms in an atmosphere of the buffer inert gases. It
should be noted that the presented approach can be naturally generalized in order to
describe the energy and spectral characteristics of other atomic systems and buffer
mediums.
The calculation results on the hyperfine line collision shift and broadening for
the alkali (Rb, Cs), thallium, and ytterbium atoms in an atmosphere of the inert gas
(He, Kr, Xe) are listed and compared with available alternative theoretical and
experimental results. The obtained data for the (Г a /p)/f p ratio allowed to confirm
that the well-known Foley law Г a * f p in the theory of optical range spectral line
broadening is incorrect for the spectral lines of transitions between components of
the hyperfine structure of the heavy multielectron atoms.
The studying hyperfine structure line collision shifts and widths for different
heavy atomic systems in the buffer gases opens new prospects in the bridging of
quantum chemistry and atomic and molecular spectroscopy and physics of collisions. These possibilities are significantly strengthened by a modern experimental
laser and other technologies [22–24, 98–106]. Really, new experimental technologies in physics of collisions may provide a measurement of the atomic and
molecular collision spectral parameters with very high accuracy.
Acknowledgments The support of the Odessa State University—OSENU as well as of the
Ministry of Education and Science of Ukraine (2013) is acknowledged. The author would like to
thank Prof. Marco Nascimento for his invitation to present this contribution at QSCP-XVIII
(Paraty, Rio de Janeiro, Brazil), and Prof. Andrey N. Starostin (Centre for Theoretical Physics and
Computational Mathematics, Research State Center of the Russian Federation “Troitsk Institute for
Innovation and Fusion Research”, Troitsk, Russian Federation) and Vladimir G. Shevchuk
(Department of Chemical Physics, Odessa National University, Odessa, Ukraine) for useful
comments.
Optimized Perturbation Theory for Calculating the Hyperfine …
73