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Accounting for correlations with core electrons by means of the generalized relativistic effective core potentials: Atoms Hg and Pb and their compounds
A way to account for correlations between the chemically active (valence) and
innermore (core) electrons in the framework of the generalized relativistic
effective core potential (GRECP) method is suggested. The "correlated" GRECP's
(CGRECP's) are generated for the Hg and Pb atoms. Only correlations for the
external twelve and four electrons of them, correspondingly, should be treated
explicitly in the subsequent calculations with these CGRECP's whereas the
innermore electrons are excluded from the calculations. Results of atomic
calculations with the correlated and earlier GRECP versions are compared with
the corresponding all-electron Dirac-Coulomb values. Calculations with the
above GRECP's and CGRECP's are also carried out for the lowest-lying states of
the HgH molecule and its cation and for the ground state of the PbO molecule as
compared to earlier calculations and experimental data. The accuracy for the
vibrational frequencies is increased up to an order of magnitude and the errors
for the bond lengths (rotational constants) are decreased in about two times
when the correlated GRECP's are applied instead of earlier GRECP versions
employing the same innercore-outercore-valence partitioning.Comment: 12 pages, 4 tables, the text of the paper was significantly improve
Towards the electron EDM search: Theoretical study of HfF+
We report first ab initio relativistic correlation calculations of potential
curves for ten low-lying electronic states, effective electric field on the
electron and hyperfine constants for the ^3\Delta_1 state of cation of a heavy
transition metal fluoride, HfF^+, that is suggested to be used as the working
state in experiments to search for the electric dipole moment of the electron.
It is shown that HfF^+ has deeply bound ^1\Sigma^+ ground state, its
dissociation energy is D_e=6.4 eV. The ^3\Delta_1 state is obtained to be the
relatively long-lived first excited state lying about 0.2 eV higher. The
calculated effective electric field E_eff=W_d|\Omega| acting on an electron in
this state is 5.84*10^{24}Hz/(e*cm)Comment: 4 page
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