Optimized Perturbation Theory for
Calculating the Hyperfine Line Shift
and Broadening of Heavy Atoms
in a Buffer Gas
Olga Yu. Khetselius
Abstract A consistent relativistic approach, based on the atomic gauge-invariant
relativistic perturbation theory and the exchange perturbation theory, is presented
and applied to calculating the interatomic potentials, van der Waals constants,
hyperfine structure line collision shift and broadening for heavy atoms in an
atmosphere of the buffer inert gas. The corresponding data on the collision
hyperfine line shift and broadening for the thallium, alkali (Rb, Cs) and lanthanide
(ytterbium) atoms in an atmosphere of the inert gas (He, Kr, Xe) are listed and
compared with available alternative theoretical and experimental results.
Keywords Relativistic many-body perturbation theory Á Exchange perturbation
theory Á Interatomic potentials and hyperfine line collision shifts Á Alkali and
lanthanide atoms in a buffer gas
1 Introduction
The broadening and shift of atomic spectral lines by collisions with neutral atoms
has been studied extensively since the very beginning of atomic physics, physics of
collisions etc. [1–12]. High precision data on the collisional shift and broadening of
the hyperfine structure lines of heavy elements (alkali, alkali-earth, lanthanides,
actinides and others) in an atmosphere of the buffer (for example, inert) gases are of
a great interest for modern quantum chemistry, atomic and molecular spectroscopy,
astrophysics and metrology as well as for studying a role of weak interactions in
atomic optics and heavy-elements chemistry [1–24]. As a rule, the cited spectral
lines shift and broadening due to a collision of the emitting atoms with the buffer
atoms are very sensitive to a kind of the intermolecular interaction. It means that
O.Yu. Khetselius (&)
Odessa State Environmental University (OSENU),
L’vovskaya Str., 15, Odessa-9 65016, Ukraine
e-mail: okhetsel@gmail.com
© Springer International Publishing Switzerland 2015
M.A.C. Nascimento et al. (eds.), Frontiers in Quantum Methods and Applications
in Chemistry and Physics, Progress in Theoretical Chemistry and Physics 29,
DOI 10.1007/978-3-319-14397-2_4
55
Calculating the Hyperfine Line Shift
and Broadening of Heavy Atoms
in a Buffer Gas
Olga Yu. Khetselius
Abstract A consistent relativistic approach, based on the atomic gauge-invariant
relativistic perturbation theory and the exchange perturbation theory, is presented
and applied to calculating the interatomic potentials, van der Waals constants,
hyperfine structure line collision shift and broadening for heavy atoms in an
atmosphere of the buffer inert gas. The corresponding data on the collision
hyperfine line shift and broadening for the thallium, alkali (Rb, Cs) and lanthanide
(ytterbium) atoms in an atmosphere of the inert gas (He, Kr, Xe) are listed and
compared with available alternative theoretical and experimental results.
Keywords Relativistic many-body perturbation theory Á Exchange perturbation
theory Á Interatomic potentials and hyperfine line collision shifts Á Alkali and
lanthanide atoms in a buffer gas
1 Introduction
The broadening and shift of atomic spectral lines by collisions with neutral atoms
has been studied extensively since the very beginning of atomic physics, physics of
collisions etc. [1–12]. High precision data on the collisional shift and broadening of
the hyperfine structure lines of heavy elements (alkali, alkali-earth, lanthanides,
actinides and others) in an atmosphere of the buffer (for example, inert) gases are of
a great interest for modern quantum chemistry, atomic and molecular spectroscopy,
astrophysics and metrology as well as for studying a role of weak interactions in
atomic optics and heavy-elements chemistry [1–24]. As a rule, the cited spectral
lines shift and broadening due to a collision of the emitting atoms with the buffer
atoms are very sensitive to a kind of the intermolecular interaction. It means that
O.Yu. Khetselius (&)
Odessa State Environmental University (OSENU),
L’vovskaya Str., 15, Odessa-9 65016, Ukraine
e-mail: okhetsel@gmail.com
© Springer International Publishing Switzerland 2015
M.A.C. Nascimento et al. (eds.), Frontiers in Quantum Methods and Applications
in Chemistry and Physics, Progress in Theoretical Chemistry and Physics 29,
DOI 10.1007/978-3-319-14397-2_4
55