arXiv subjects

Timur Isaev

Publications and source records attributed to Timur Isaev.

5 recordsLinked to original sources

arXiv2023

Optical cycling in charged complexes with Ra-N bonds

The extension of laser cooling and trapping techniques to polyatomic molecular ions would have advanced scientific applications such as search of physics outside of the Standard Model, ultracold chemistry etc. We apply the Fock space relativistic coupled cluster method to study low-lying electronic states of molecular ions with Ra--N bonds, namely RaNCH$^+$, RaNH$^+_3$ and RaNCCH$^+_3$. Prospects of laser cooling of these species are estimated, and the peculiarities of unpaired-electron distributions are analyzed from the point of view of the molecular electronic structure. RaNH$^+_3$ and RaNCCH$^+_3$ are the first symmetric top molecular ions expected to be suitable for direct laser cooling.

physics.atom-ph↗

arXiv2022

Radium-containing molecular cations amenable for laser cooling

Recently a new wave of interest to spectroscopy of radioactive compounds has raised due to successful applications of the new experimental ISOL/CRIS technique to optical spectroscopy of radium monofluoride molecules. This opens great prospects to searches of the effects connected with ``new physics'' which point on deviations of the physical laws from those established by Standard Model of elementary particles. Considerable advantages in experiments for search for such effects would be provided by the abilities to trap the working molecules, their laser-coolability and presence of co-magnitometer molecular states and also a variety of accessible nuclear isotopes of the elements in the molecule with different nuclear multipole moments. Laser-coolable polyatomic molecular ions containing Ra nuclei shall meet the above criteria and in the present article we are considering a number of prospective molecular ions and calculating their electronic structure and molecular properties.

physics.chem-ph↗

arXiv2021

Accurate \textit{ab initio} calculations of RaF electronic structure indicate the need for more laser-spectroscopical measurements

Recently a breakthrough has been achieved in laser-spectroscopic studies of short-lived radioactive compounds with the first measurements of the radium monofluoride molecule (RaF) UV/vis spectra. We report results from high accuracy \emph{ab initio} calculations of the RaF electronic structure for ground and low-lying excited electronic states. Two different methods agree excellently with experimental excitation energies from the electronic ground state to the $^2\Pi_{1/2}$ and $^2\Pi_{3/2}$ states, but lead consistently and unambiguously to deviations from experimental-based adiabatic transition energy estimates for the $^2\Sigma_{1/2}$ excited electronic state and show that more measurements are needed to clarify spectroscopic assignment of the $^2\Delta$ states.

physics.atom-ph↗

arXiv2018

Systematic study of relativistic and chemical enhancements of $\mathcal{P,T}$-odd effects in polar diatomic radicals

Polar diatomic molecules that have, or are expected to have a $^2\Sigma_{1/2}$-ground state are studied systematically with respect to simultaneous violation of parity $\mathcal{P}$ and time-reversal $\mathcal{T}$ with numerical methods and analytical models. Enhancements of $\mathcal{P,T}$-violating effects due to an electric dipole moment of the electron (eEDM) and $\mathcal{P,T}$-odd scalar-pseudoscalar nucleon-electron current interactions are analyzed by comparing trends within columns and rows of the periodic table of the elements. For this purpose electronic structure parameters are calculated numerically within a quasi-relativistic zeroth order regular approximation (ZORA) approach in the framework of complex generalized Hartree-Fock (cGHF) or Kohn-Sham (cGKS). Scaling relations known from analytic relativistic atomic structure theory are compared to these numerical results. Based on this analysis, problems of commonly used relativistic enhancement factors are discussed. Furthermore the ratio between both $\mathcal{P,T}$-odd electronic structure parameters mentioned above is analyzed for various groups of the periodic table. From this analysis an analytic measure for the disentanglement of the two $\mathcal{P,T}$-odd electronic structure parameters with multiple experiments in dependence of electronic structure enhancement factors is derived.

physics.chem-ph↗

arXiv2016

Polyatomic candidates for cooling of molecules with lasers from simple theoretical concepts

A rational approach to identify polyatomic molecules that appear to be promising candidates for direct Doppler cooling with lasers is outlined. First-principle calculations for equilibrium structures and Franck--Condon factors of selected representatives with different point-group symmetries (including chiral non-symmetric group C$_1$) have been performed and high potential for laser-cooling of these molecules is indicated.

physics.chem-ph↗