Erratum: “Quantum Monte Carlo study of the ground state and low-lying excited states of the scandium dimer” [J. Chem. Phys. 128, 194315 (2008)]

Matxain, Jon M.; Rezabal, Elixabete; López, Xabier; Ugalde, Jesus M.; Gagliardi, Laura

doi:10.1063/1.3372793

Cited by 13 publications

(24 citation statements)

References 7 publications

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“…Matxain et al [43], applying the quantum diffusion Monte Carlo (DMC) method, obtained the 3 Σ u state as more stable by 0.17 eV than the state. The authors [43] claimed that the correct ground state of scandium…”

Section: Account Of Published Studiesmentioning

confidence: 95%

“…However, the calculations by Matxain et al [43] did not have a sufficient level of accuracy to be reliable. The authors [43] used a relatively small basis set and checked the DMC results comparing it with CASPT2 calculation (the latter is taken as a final criteria). How ever, the CASPT2 method is very sensitive to the choice of the active space and the use of non closed active space can lead to large errors [55,56].…”

Section: Account Of Published Studiesmentioning

confidence: 98%

“…In 2008 Matxain et al [43] revised the problem of the Sc 2 ground state. They stressed that only the state had been studied at a high level [41,42], whereas the triplet terms were calculated in [41] using the not sufficiently precise CASSCF approach.…”

Section: Account Of Published Studiesmentioning

confidence: 99%

“…They stressed that only the state had been studied at a high level [41,42], whereas the triplet terms were calculated in [41] using the not sufficiently precise CASSCF approach. Matxain et al [43], applying the quantum diffusion Monte Carlo (DMC) method, obtained the 3 Σ u state as more stable by 0.17 eV than the state. The authors [43] claimed that the correct ground state of scandium…”

Section: Account Of Published Studiesmentioning

confidence: 99%

“…11 2014 dimer is the 3 Σ u state, but not the state, as was accepted in all previous investigations. However, the calculations by Matxain et al [43] did not have a sufficient level of accuracy to be reliable. The authors [43] used a relatively small basis set and checked the DMC results comparing it with CASPT2 calculation (the latter is taken as a final criteria).…”

Section: Account Of Published Studiesmentioning

confidence: 99%

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Multi-reference Ab initio calculations of 3d transition-metal dimers: Sc2

Kaplan

Miranda

2014

Russ. J. Phys. Chem.

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The problem of calculation of the electronic structure of transition metal clusters (even dimers) still presents a challenge for computational chemistry. The reason is that the expansion of the ground state wave function on electronic configurations does not contain a principal configuration and a large number of reference configurations must be treated equally. Thus, the multi reference (MR) approaches are, in general, mandatory. A short description of the MRCI methods is presented. The calculation of Sc 2 at the MRCISD(+Q)/cc pV5Z level, showed that the its ground state corresponds to a quintet, , in agreement with experiment and previous precise calculations. The triplet state is located about 1.1 kcal/mol above.We calculated the ground state, X , of the Sc 2 dimer by the MRCISD(+Q) method at the complete basis set (CBS) limit. This is the first MRCISD(+Q) calculation of 3d transition metal clusters at the CBS limit. From the Mulliken population analysis and comparison with atomic energies follows that in the ground state Sc 2 dissociates on one Sc in the ground state and the other in the second excited quartet state, 4 F u . The spec troscopic parameters of the ground potential curve, obtained by the Dunham analysis at the valence MRCISD(+Q)/CBS level, are: R e = 5.20 bohr, D e = 50.37 kcal/mol, and e = 234.5 cm -1 . The obtained value for the harmonic frequency agrees very well with the experimental one, e = 239.9 cm -1 . From the indistin guishability of identical atoms in quantum mechanics follows that in spite of an asymmetric dissociation limit for Sc 2 , both Sc atoms have the same electron population and it is incorrect to consider them as different. Therefore, the accepted classification of the dimer states should be revised, since some of them are forbidden by the Pauli Exclusion Principle.Keywords: 3d transition metal dimers, Sc 2 , multi reference configuration interaction (MRCI), complete basis set limit.

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Section: Account Of Published Studiesmentioning

confidence: 95%

Section: Account Of Published Studiesmentioning

confidence: 98%

Section: Account Of Published Studiesmentioning

confidence: 99%

Section: Account Of Published Studiesmentioning

confidence: 99%

Section: Account Of Published Studiesmentioning

confidence: 99%

See 3 more Smart Citations

Multi-reference Ab initio calculations of 3d transition-metal dimers: Sc2

Kaplan

Miranda

2014

Russ. J. Phys. Chem.

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Unitary perturbation theory applied to multiconfigurational reference functions

Nagy

Szabados

2012

Int J of Quantum Chemistry

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Unitary parametrization of the wave operator in the form suggested by Mayer is studied in the multireference framework. The investigated unitary perturbation theory (UPT) constructs a first correction in terms of the functions having nonzero interaction with the reference state via the Hamiltonian. Parameters in the exponential of the wave operator are determined by two dimensional eigenvalue equations. Because of the unitary mapping, UPT is unaffected by the quasi-degeneracy problem, making it an ideal tool for correcting multireference starting functions. Lack of size-consistency is however a shortcoming of the method.Applications of UPT as well as the related degeneracy-corrected PT (DCPT) are presented on intruder prone examples like the symmetric dissociation of the water molecule, the BeH 2 system and the two lowest lying states of the scandium dimer. Size consistency violation is analysed and evaluated on the example of the water dimer. Tractability of excited states by UPT is examined by computing the singlet-triplet splitting of the CH 2 molecule.

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State-of-the-Art Calculations of the 3d Transition-Metal Dimers: Mn2 and Sc2

Kaplan

Miranda

2012

Practical Aspects of Computational Chemistry II

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Erratum: “Quantum Monte Carlo study of the ground state and low-lying excited states of the scandium dimer” [J. Chem. Phys. 128, 194315 (2008)]

Cited by 13 publications

References 7 publications

Multi-reference Ab initio calculations of 3d transition-metal dimers: Sc2

Multi-reference Ab initio calculations of 3d transition-metal dimers: Sc2

Unitary perturbation theory applied to multiconfigurational reference functions

State-of-the-Art Calculations of the 3d Transition-Metal Dimers: Mn2 and Sc2

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