133 research outputs found
Theoretical study of ThF in the search for T,P-violation effects: Effective state of a Th atom in ThF and ThO compounds
We report the results of theoretical investigation of electronic structure of
ThF cation which is one of the most interesting systems to search for the
electron electric dipole moment (eEDM) [H. Loh, K.C. Cossel, M.C. Grau, K.-K.
Ni, E.R. Meyer, J.L. Bohn, J. Ye, E.A. Cornell, Science {\bf 342}, 1220 (2013)]
and other effects of violation of time reversal (T) and spacial parity (P)
symmetries in fundamental interactions. For the working state we
have found a quite high value of the effective electric field acting on
unpaired electrons (37.3 GV/cm). The field will be required to interpret the
experiment planed on ThF in terms of eEDM. Within the concept of atoms in
compounds [A.V. Titov, Y.V. Lomachuk, and L.V. Skripnikov, Phys. Rev. A {\bf
90}, 052522 (2014)] we have compared the ThF electronic structure with that
of ThO. Also we have calculated other parameters of T,P-odd interactions:
, which is needed for interpretation of the experiment in terms of the
dimensionless constant characterizing the strength of the T,P-odd
pseudoscalarscalar electronnucleus neutral current interaction (50 kHz);
, which is required to search for the Th nuclear magnetic quadrupole
moment in ThF (0.88 ). A
number of properties which can be measured are also calculated: hyperfine
structure constant, the molecule-frame dipole moment, and g-factor
Theoretical study of the parity and time reversal violating interaction in solids
A new theoretical approach to study the properties in solids, which are
sensitive to a change of densities of the valence electrons in atomic cores
(hyperfine structure constants, parameters of space parity (P) and time
reversal (T) violation interaction, etc.) is proposed and implemented. It uses
the two-step concept of calculation of such properties which was implemented
earlier for the case of molecules [Progr.\ Theor.\ Chem.\ Phys. B 15, 253
(2006)]. The approach is applied to evaluate the parameter describing
electronic density gradient on the Pb nucleus that is required to interpret the
proposed experiment on PbTiO crystal [PRA, 72, 034501 (2005)] to search for
the Schiff moment of the Pb nucleus because of its high sensitivity to
the corresponding P,T-violating interactions. For comparison the parameter
has also been calculated on the Pb nucleus for the state of
PbO molecule using the same density functionals as those utilized in
PbTiO studies. The relativistic coupled-clusters approach with single,
double and perturbative triple cluster amplitudes, applicable to a few atom
systems and providing high accuracy for , is also applied to the PbO case to
estimate the accuracy of density functional studies
Theoretical study of ThO for the electron electric dipole moment search
An experiment to search for the electron electric dipole moment (\eEDM) on
the metastable state of ThO molecule was proposed and now in the
final stage of preparation by the ACME collaboration
[http://www.electronedm.org]. To interpret the experiment in terms of \eEDM\
and dimensionless constant characterizing the strength of the scalar
T,P-odd electron-nucleus neutral current interaction, an accurate theoretical
study of effective electric field on electron, Eeff, and constants is
required. We report calculation of \Eeff\ (84 GV/cm) and a parameter of T,P-odd
scalar neutral currents interaction, (116 kHz), together with the
hyperfine structure constant, molecule frame dipole moment and transition energy, which can serve as a measure of reliability of
the obtained \Eeff\ and values. Besides, our results include a parity
assignment and evaluation of the electric-field dependence for the magnetic
factors for the -doublets of
Many body study of -factor in boron-like argon
Highly accurate measurements of the -factor of boronlike Ar are currently
implemented within the ARTEMIS experiment at GSI (Darmstadt, Germany) and
within the ALPHATRAP experiment at the MPIK (Heidelberg, Germany). A comparison
with the corresponding theoretical predictions will allow one to test the
modern methods of bound-state QED. However, at least three different
theoretical values of the \emph{g}-factor have been published up to date. The
systematic study of the \emph{g} factor value of Ar in the ground
and the first excited
states is performed within the high order coupled cluster and configuration
interaction theories up to the full configuration interaction treatment.
Correlation contributions are discussed and results are compared with previous
studies.Comment: 7 pages, no figure
Evaluation of CP-violation in HfF
CP violation effects produced by the nuclear magnetic quadrupole moment
(MQM), electron electric dipole moment (EDM) and scalarpseudoscalar
nucleuselectron neutral current (SP) interaction in HfF
and HfF are calculated. The role of the hyperfine
interaction is investigated. It is shown that the MQM shift can be
distinguished from the electron EDM and SP ones due to the implicit dependence
of MQM shift on the hyperfine sublevel. The MQM effect is expressed in terms of
the proton (EDM), QCD vacuum angle and quark chromo-EDMs
Centrifugal correction to hyperfine structure constants in the ground state of lead monofluoride, PbF
The sensitivity of the PbF molecule to the electron electric dipole moment
has motivated detailed microwave spectroscopy. Previous theoretical approaches
cannot fully explain the spectra. In turn, the explanation from "first
principles" is very important both for molecular theory and for confirmation of
the correctness of the interpretation of experimental data obtained with high
precision. All of these issues are decisively addressed here. We have
determined centrifugal correction parameters for hyperfine structure constants,
both on lead and fluorine nuclei, of the state of lead
monofluoride. These parameters were obtained by fitting experimentally observed
pure rotational transitions and from {\it ab initio} calculations. We show that
taking this correction into account is required to reproduce the experimental
transition energies obtained in [Phys. Rev. A 84, 022508 (2011)]
Manifestations of nuclear CP-violation in ThO molecule
Investigations of CP violation in hadron sector may be done using
measurements in the ThO molecule. Recent measurements in this molecule improved
the limit on electron EDM by an order of magnitude. Another time reversal (T)
and parity (P) violating effect in ThO is induced by the nuclear
magnetic quadrupole moment. We have performed nuclear and molecular
calculations to express this effect in terms of the strength constants of
T,P-odd nuclear forces, neutron EDM, QCD vacuum angle , quark EDM and
chromo-EDM
TaN molecule as a candidate to search for New physics
It is demonstrated that the TaN molecule is the best candidate to search for
T,P-violating nuclear magnetic quadrupole moment (MQM), it also looks promising
to search for other T,P-odd effects. We report results of coupled-cluster
calculations of T,P-odd effects in TaN produced by the Ta nucleus MQM, electron
electric dipole moment (EDM), scalarpseudoscalar nucleuselectron
interactions, also of the molecule-axis hyperfine structure constant and dipole
moment. Nuclear calculations of Ta MQM are performed to express the
T,P-odd effect in terms of the strength constants of T,P-odd nuclear forces,
proton and neutron EDM, QCD parameter and quark chromo-EDM
Towards the search of electron electric dipole moment: correlation calculations of the P,T-violation effect in the Eu cation
Recently the EuBaTiO solid was suggested as a promising
candidate for experimental search of the electron electric dipole moment. To
interpret the results of this experiment one should calculate the effective
electric field acting on an unpaired (spin-polarized) electrons of europium
cation in the crystal because the value of this field cannot be measured
experimentally. The Eu cation is considered in the paper in the uniform
external electric field as our first and simplest model
simulating the state of europium in the crystal. We have performed high-level
electronic structure correlation calculation using coupled clusters theory (and
scalar-relativistic approximation for valence and outer core electrons at the
molecular pseudopotential calculation stage that is followed by the
four-component spinor restoration of the core electronic structure) to evaluate
the enhancement coefficient (where
is the applied external electric field and is the induced
effective electric field acting on an unpaired electron in Eu). A
detailed computation analysis is presented. The calculated value of is
-4.6
Calculation of the parity and time reversal violating interaction in ^{225}RaO
The 10-electron generalized relativistic effective core potential and the
corresponding correlation spin-orbital basis sets are generated for the Ra atom
and the relativistic coupled cluster calculations for the RaO molecule are
performed. The main goal of the study is to evaluate the P,T-odd parameter X
characterized by the molecular electronic structure and corresponding to a
"volume effect" in the interaction of the ^{225}Ra nucleus Schiff moment with
electronic shells of RaO. Our final result for X(^{225}RaO) is -7532 which is
surprisingly close to that in ^{205}TlF but has different sign. The obtained
results are discussed and the quality of the calculations is analyzed. The
value is of interest for a proposed experiment on RaO [PRA 77, 024501 (2008)]
due to a very large expected Schiff moment of the ^{225}Ra nucleus.Comment: 5 pages, corrected the erroneous signs of H_eff and w_ex_e from
10.1103/PhysRevA.87.02010
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