31 research outputs found
Molecular enhancement factors for P, T-violating eEDM in BaCH and YbCH symmetric top molecules
High-precision tests of fundamental symmetries are looking for the parity-
(P), time-reversal- (T) violating electric dipole moment of the electron (eEDM)
as proof of physics beyond the Standard Model. Particularly, in polyatomic
molecules, the complex vibrational and rotational structure gives the
possibility to reach high enhancement of the P, T-odd effects in moderate
electric fields. Additionally, it is possible to increase the statistical
sensitivity by using laser cooling. In this work, we calculate the P, T-odd
electronic structure parameters and for the
promising candidates BaCH and YbCH for the interpretation of future
experiments. We employ high-accuracy relativistic coupled cluster methods and
systematically evaluate the uncertainties of our computational approach.
Compared to other Ba- and Yb-containing molecules, BaCH and YbCH
exhibit larger and associated to increased
covalent character of the M--C bond. The calculated values are and for , and
~kHz and ~kHz for , in BaCH
and YbCH, respectively. The robust, accurate, and cost-effective
computational scheme reported in this work makes our results suitable for
extracting the relevant fundamental properties from future measurements and
also can be used to explore other polyatomic molecules sensitive to various
violations of fundamental symmetries
High accuracy theoretical investigations of CaF, SrF, and BaF and implications for laser-cooling
The NL-eEDM collaboration is building an experimental setup to search for the
permanent electric dipole moment of the electron in a slow beam of cold barium
fluoride molecules [Eur. Phys. J. D, 72, 197 (2018)]. Knowledge of molecular
properties of BaF is thus needed to plan the measurements and in particular to
determine an optimal laser-cooling scheme. Accurate and reliable theoretical
predictions of these properties require incorporation of both high-order
correlation and relativistic effects in the calculations. In this work
theoretical investigations of the ground and the lowest excited states of BaF
and its lighter homologues, CaF and SrF, are carried out in the framework of
the relativistic Fock-space coupled cluster (FSCC) and multireference
configuration interaction (MRCI) methods. Using the calculated molecular
properties, we determine the Franck-Condon factors (FCFs) for the transition, which was successfully used for
cooling CaF and SrF and is now considered for BaF. For all three species, the
FCFs are found to be highly diagonal. Calculations are also performed for the
transition recently
exploited for laser-cooling of CaF; it is shown that this transition is not
suitable for laser-cooling of BaF, due to the non-diagonal nature of the FCFs
in this system. Special attention is given to the properties of the
state, which in the case of BaF causes a leak channel, in contrast
to CaF and SrF species where this state is energetically above the excited
states used in laser-cooling. We also present the dipole moments of the ground
and the excited states of the three molecules and the transition dipole moments
(TDMs) between the different states.Comment: Minor changes; The following article has been submitted to the
Journal of Chemical Physics. After it is published, it will be found at
https://publishing.aip.org/resources/librarians/products/journals
On the estimation of structural index from low-pass filtered magnetic data
We compare the effect of the smoothing of magnetic data on the estimation of the structural index by Euler deconvolution. We analyze physically-based as well as mathematical filters. In general, we found that low-pass filtering the data leads to an increase of the estimated structural index
Microgravity method in archaeological prospection: Methodical comments on selected case studies from Slovakia
The use of microgravity technique in archaeology: A case study from the St. Nicolas Church in Pukanec, Slovakia
Theoretical determination of the ionization potentials of CaF, SrF, and BaF
We present a comprehensive theoretical study of the ionization potentials of the MF (M=Ca, Sr, and Ba) molecules using the state-of-the-art relativistic coupled-cluster approach with single, double, and perturbative triple excitations [CCSD(T)]. We have further corrected our results for higher-order excitations (up to full triples) and the QED self-energy and vacuum-polarization contributions. We have performed an extensive investigation of the effect of the various computational parameters on the calculated ionization potentials, which allowed us to assign realistic uncertainties to our predictions. For CaF and BaF, where precise experimental measurements are available, our predictions are in excellent agreement with the measured values. In the case of SrF, we provide a theoretical prediction of the ionization potential that deviates from the available experimental measurements, motivating further experimental investigations.</p
Molecular enhancement factors for the P, T -violating electric dipole moment of the electron in BaCH3 and YbCH3 symmetric top molecules
High-precision tests of fundamental symmetries are looking for the parity- (P), time-reversal- (T) violating electric dipole moment of the electron (eEDM) as proof of physics beyond the Standard Model. Particularly, in polyatomic molecules, the complex vibrational and rotational structure gives the possibility to reach high enhancement of the P,T-odd effects in moderate electric fields, and with the possibility of increasing the statistical sensitivity by using laser cooling. In this work, we calculate the P,T-odd molecular enhancement factor of the eEDM (Wd) and of the scalar-pseudoscalar interaction (Ws) necessary for the interpretation of future experiments on the promising candidates BaCH3 and YbCH3. We employ high-accuracy relativistic coupled cluster methods and systematically evaluate the uncertainties of our computational approach. Compared to other Ba- and Yb-containing molecules, BaCH3 and YbCH3 exhibit larger Wd and Ws associated to the increased covalent character of the M-C bond. The calculated values are 3.22±0.12×1024hHzecm and 13.80±0.35×1024hHzecm for Wd, and 8.42±0.29hkHz and 50.16±1.27hkHz for Ws, in BaCH3 and YbCH3, respectively. The robust, accurate, and cost-effective computational scheme reported in this work makes our results suitable for extracting the relevant fundamental properties from future measurements and also can be used to explore other polyatomic molecules sensitive to various violations of fundamental symmetries
Toward Detection of the Molecular Parity Violation in Chiral Ru(acac)(3) and Os(acac)(3)
International audienceWe present a theory-experiment investigation of the helically chiral compounds Ru(acac)(3) and Os(acac)(3) as candidates for next-generation experiments for detection of molecular parity violation (PV) in vibrational spectra. We used relativistic density functional theory calculations to identify optimal vibrational modes with expected PV effects exceeding by up to 2 orders of magnitude the projected instrumental sensitivity of the ultrahigh resolution experiment under construction at the Laboratoire de Physique des Lasers in Paris. Preliminary measurements of the vibrational spectrum of Ru(acac)(3) carried out as the first steps toward the planned experiment are presented