Towards highly accurate calculations of parity violation in chiral molecules: relativistic coupled-cluster theory including QED-effects

Sunaga, Ayaki; Saue, Trond

doi:10.1080/00268976.2021.1974592

Cited by 19 publications

(19 citation statements)

References 153 publications

(180 reference statements)

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“…20 and 63. The final basis set LBas consists of 39 s−, 33 p−, 26 d−, 13 f −, 9 g−, 6 h− and 3 i− type uncontracted Gaussian functions, which can be designated as [39,33,26,13,9,6,3]. Next, we calculated basis set extension correction.…”

Section: Resultsmentioning

confidence: 99%

The role of QED effects in transition energies of heavy-atom alkaline earth monofluoride molecules: a theoretical study of Ba$^+$, BaF, RaF and E120F

Skripnikov,

Chubukov,

Shakhova

2021

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Heavy-atom alkaline earth monofluoride molecules are considered as prospective systems to study spatial parity or spatial parity and time-reversal symmetry violating effects such as the nuclear anapole moment or the electron electric dipole moment. Comprehensive and highly accurate theoretical study of the electronic structure properties and transition energies in such systems can simplify the preparation and interpretation of the experiments. However, almost no attempts to calculate quantum electrodynamics (QED) effects contribution into characteristics of neutral heavy-atom molecules have been performed. Recently, we have formulated and implemented such an approach to calculate QED contributions to transition energies of molecules [L.V. Skripnikov, J. Chem. Phys. 154, 201101 (2021)]. In this paper, we perform a benchmark theoretical study of the transition energies in the Ba + cation and BaF molecule. The deviation of the calculated values from the experimental ones is of the order 10 cm −1 and is more than an order of magnitude better than the "chemical accuracy", 350 cm −1 . The achievement of such an agreement has been provided in particular by the inclusion of the QED effects. The latter appeared to be not less important than the high-order correlation effects beyond the coupled cluster with single, double, and perturbative triple cluster amplitudes level. We compare the role of QED effects for transition energies with heavier molecules -RaF and E120F, where E120 is the superheavy Z=120 homolog of Ra.

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Section: Resultsmentioning

confidence: 99%

The role of QED effects in transition energies of heavy-atom alkaline earth monofluoride molecules: a theoretical study of Ba$^+$, BaF, RaF and E120F

Skripnikov,

Chubukov,

Shakhova

2021

Preprint

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“…Detection of parity violation (PV) effects, associated with weak force in atoms and molecules is an active field of research 13,74,75 . While this property can also be computed with perturbation theory starting from nonrelativistic theory 76 , it is advantageous to use a relativistic quantum chemistry framework because the PV energy can then be formulated as an expectation value of an effective one-body operator 67 :…”

Section: Parity Violationmentioning

confidence: 99%

“…Sunaga et al 13 already investigated use of CMO truncation at CCSD level with two different threshold values and showed that truncation is well possible for this property. In current work, we also employ FNO truncation and test more thresholds for CMO truncation and its effect on the PV value.…”

Section: Parity Violationmentioning

confidence: 99%

“…In the particular case of relativistic electronic structure calculations, DFT energies may even for closed-shell species strongly deviate from experimental or accurate theoretical results [10][11][12] . This also holds for molecular properties, recently Sunaga and Saue 13 reported that the performance of DFT for parity violation energy shift (PV) calculations -a property requiring a very accurate description of the electronic wave function near the nuclei -is somewhat disappointing, with deviations to CCSD being as large as 10%. These uncertainties in the performance of of DFT for heavy elements, especially for cases in which experimental values are absent or difficult to generate, calls for the use of state-of-the-art wavefunction methods to either provide accurate reference data, or be applied directly a) Electronic mail: xiang.yuan@univ-lille.fr b) Electronic mail: l.visscher@vu.nl c) Electronic mail: andre.gomes@univ-lille.fr if the model sizes are small enough.…”

Section: Introductionmentioning

confidence: 99%

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Assessing MP2 frozen natural orbitals in relativistic correlated electronic structure calculations

Yuan,

Visscher,

Gomes

2022

Preprint

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The high computational scaling with the number of correlated electrons and the size of the basis set is a bottleneck which limits applications of coupled cluster (CC) algorithms. This is particularly so for calculations based on 4-component relativistic Hamiltonians, which generally employ uncontracted basis sets and lead to large virtual molecular orbital (VMO) spaces. This problem may be alleviated by employing a more compact set of virtual spinors than those provided by the canonical Hartree-Fock (HF) set, such as those based on natural orbitals (NOs). In this paper we describe the implementation of a module for generating NOs for correlated wavefunctions, and in particular MP2 frozen natural orbitals (MP2FNOs), as a component of our novel implementation of relativistic coupled cluster theory for massively parallel architectures [J. Pototschnig et. al. J. Chem. Theory Comput. 17, 5509, 2021]. Our implementation is capable of manipulating both complex and quaternion density matrices, thus allowing for the generation of both Kramersrestricted and Kramers-unrestricted MP2FNOs. Furthermore, NOs are re-expressed in the parent atomic orbital (AO) basis, so that the code also makes it possible to generate CCSD natural orbitals in AO basis for further analysis. By investigating the truncation errors of MP2FNOs for both the correlation energy and molecular properties at CCSD level such as the electric field gradients at the nuclei (EFGs), electric dipole and quadrupole moments for hydrogen halides HX (X=F, Cl, Br, I, At, Ts), and parity-violating energy differences (PV) for H 2 Y 2 (Y=O, S, Se), we find that MP2FNOs accelerate the convergence of the correlation energy in a roughly uniform manner across the periodic table and that, with VMO spaces truncated to around half the size of the full spaces ones, it is possible to obtain reliable estimates for both energies and all molecular properties considered.Recently, Pototschnig et al. 36 described a new, efficient relativistic coupled cluster implementation based on ExaTEN-SOR 37 , a distributed numerical tensor algebra library for GPU-accelerated HPC platforms. This code enabled the calculation of molecular properties with CCSD wave functions for systems such as [(UO 2 )(NO 3 ) 3 ] − , for which 200 elec-

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“…For convenience, we have collected our HF, MP2 and CC results in Table 6 of the Supplemental Material together with previous results [51,61,62] calculated at the same geometries [55]. Our outputs are available via the zenodo repository [151].…”

Section: Computational Detailsmentioning

confidence: 99%