Application of relativistic coupled-cluster theory to heavy atomic systems with strongly interacting configurations: Hyperfine interactions in ²°â·Pb{sup (original) (raw)
Related papers
Physical Review A, 2005
An accurate determination of the effective electric field (E eff ) in YbF is important, as it can be combined with the results of future experiments to give an improved new limit for the electric dipole moment of the electron. We report a relativistic coupled-cluster calculation of this quantity in which all the core electrons were excited. It surpasses the approximations made in the previous reported calculations. We obtain a value of 23.1 GV/cm for E eff in YbF with an estimated error of less than 10%. The crucial roles of the basis sets and the core excitations in our work are discussed.
Many-body effects in hyperfine interactions in 205 Pb
European Physical Journal D, 2007
Ab initio calculations have been carried out to study the magnetic dipole and electric quadrupole hyperfine structure constants of 205 Pb + . Many-body effects have been considered to all orders using the relativistic coupled-cluster theory in the singles, doubles and partial triples approximation. The trends of these effects are found to be different from atomic systems that have been studied earlier.
Physical Review A
The role of electron correlation in the hyperfine structure of alkali metals and alkaline earth metal monopositive ions in their ground electronic configuration is investigated using the Z-vector method in a relativistic coupledcluster regime within the singles and doubles approximation. The systematic effects of core-correlating functions, polarization of core electrons, and high-lying virtual functions on core electrons correlation are studied. The study reveals that the core-correlating function plays a significant role in core polarization and thus is very important for precise calculation of the wave function near the nuclear region. The inner-core electrons (1s-2p) require very high virtual energy functions for proper correlation. Therefore, the all-electron correlation treatment and the inclusion of higher-energy virtual functions are the key factors for precise calculation of the hyperfine structure constant of atoms. Our calculated values are in excellent agreement with the available experimental values, which also implies that the wave function produced by the Z-vector method is accurate enough for further calculation of the parity-and time-reversal symmetry-violating properties in atoms and molecules.
Physical Review A, 2003
The relativistic coupled-cluster method is applied to calculate the magnetic dipole hyperfine constant ''A'' of the 6s 1/2 , 6p 1/2 , 6p 3/2 , and 5d 3/2 states of singly ionized barium. After the inclusion of two-body correlation effects into the computation of the hyperfine matrix elements, the accuracy of the obtained values was significantly increased compared to earlier computations. Based on these numbers and earlier calculations of the electric dipole transitions and excitation energies, an estimate for the accuracy of the ͉͓5 p 6 ͔6s 1/2 ͘ →͉͓5p 6 ͔5d 3/2 ͘ parity-nonconserving electric dipole transition amplitude is carried out. The results suggest that for the first time, to our knowledge, a precision of better than 1% is feasible for this transition amplitude.
Physical Review A, 2015
We use perturbed relativistic coupled-cluster (PRCC) theory to compute the electric dipole polarizabilities α of Zn, Cd and Hg. The computations are done using the Dirac-Coulomb-Breit Hamiltonian with Uehling potential to incorporate vacuum polarization corrections. The triple excitations are included perturbatively in the PRCC theory, and in the unperturbed sector, it is included non-perturbatively. Our results of α, for all the three elements, are in excellent agreement with the experimental data. The other highlight of the results is the orbital energy corrections from Breit interactions. In the literature we could only get the data of Hg [1] and are near perfect match with our results. We also present the linearized equations of the cluster amplitudes, including the triple excitations, with the angular factors.
International Journal of Quantum Chemistry, 2004
Ab initio fully relativistic all-electron Dirac–Fock (DF) and nonrelativistic (NR) Hartree–Fock (HF) limit self-consistent field (SCF) benchmark molecular calculations are reported for the tetrahedral (Td) PbH4 at various Pb–H bond distances. Our fully relativistic Dirac–Fock and nonrelativistic HF calculations predict for a PbH4 bond distance of 1.75 and 1.82 Å, respectively. Both our DF and NR HF limit SCF calculations predict the ground state of PbH4 (Td) to be bound, with the predicted atomization energy (Ae) of 7.20 and 8.63 eV, respectively. There are antibinding effects due to relativity of ∼1.4 eV to the predicted atomization energy (Ae) of PbH4. Our relativistic four-component coupled-cluster singles and doubles (RCCSD) calculations, which correlate 50 electrons and include 302 active molecular spinors with energies up to ∼46 a.u. in the active space predict the relativistic second-order Møller-Plesset (RMP2), RCCSD and RCCSD (T) (RCCSD plus the triple excitation correction included perturbationally) correlation energies as −1.271, −1.161, and −1.186 hartree, respectively. The contribution of the RMP2, RCCSD, and RCCSD (T) electron correlation energies toward the atomization energy of PbH4 as predicted by our above-mentioned CC calculation is 3.78, 4.22, and 4.30 eV, respectively. We predict the NR and relativistic MP2, CCSD, and CCSD (T) atomization energies (Ae) for PbH4 at the optimized PbH bond distances as 12.72, 12.90, 1.77 and 10.98, 11.42, and 11.50 eV, respectively. With the inclusion of both the electron correlation and effects of relativity, we predict the atomization energy for PbH4 to be ∼10–11 eV. This should encourage experimentalists to devise new synthetic methods to prepare plumbane, so that its chemical and physical properties can be investigated as in the case of its lighter congeners. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Physical Review A, 2010
We demonstrate an iterative scheme for coupled-cluster properties calculations without truncating the dressed properties operator. For validation, magnetic dipole hyperfine constants of alkaline Earth ions are calculated with relativistic coupled-cluster and role of electron correlation examined. Then, a detailed analysis of the higher order terms is carried out. Based on the results, we arrive at an optimal form of the dressed operator. Which we recommend for properties calculations with relativistic coupled-cluster theory. PACS numbers: 31.15.bw, 32.10.Fn, 31.15.vj,
The Journal of Chemical Physics, 2015
The effective electric field experienced by the unpaired electron in the ground state of PbF, which is a potential candidate in the search of electron electric dipole moment due to some special characteristics, is calculated using Z-vector method in the coupled cluster single-and double-excitation approximation with four component Dirac spinor. This is an important quantity to set the upper bound limit of the electron electric dipole moment. Further, we have calculated molecular dipole moment and parallel magnetic hyperfine structure constant (A) of 207 Pb in PbF to test the accuracy of the wave function obtained in the Z-vector method. The outcome of our calculations clearly suggests that the core electrons have significant contribution to the "atom in compound (AIC)" properties.
Relativistic extended-coupled-cluster method for the magnetic hyperfine structure constant
Physical Review A, 2015
The article deals with the general implementation of 4-component spinor relativistic extended coupled cluster (ECC) method to calculate first order property of atoms and molecules in their open-shell ground state configuration. The implemented relativistic ECC is employed to calculate hyperfine structure (HFS) constant of alkali metals (Li, Na, K, Rb and Cs), singly charged alkaline earth metal atoms (Be + , Mg + , Ca + and Sr +) and molecules (BeH, MgF and CaH). We have compared our ECC results with the calculations based on restricted active space configuration interaction (RAS-CI) method. Our results are in better agreement with the available experimental values than those of the RAS-CI values.
Relativistic unitary coupled cluster theory and applications
2005
We present the first formulation and application of relativistic unitary coupled cluster theory to atomic properties. The remarkable features of this theory are highlighted, and it is used to calculate the lifetimes of 52D3/25^{2}D_{3/2}52D3/2 and 62P3/26^{2}P_{3/2}62P3/2 states of Ba+Ba^{+}Ba+ and Pb+Pb^{+}Pb+ respectively. The results clearly suggest that it is very well suited for accurate \emph{ab initio} calculations of properties of heavy atomic systems.