Spin Multiplicity and Symmetry Breaking in Vanadium-Benzene Complexes

Horvathova, Lucia; Dubecký, Matúš; Mitáš, Luboš; Štich, Ivan

doi:10.1103/physrevlett.109.053001

Cited by 36 publications

(38 citation statements)

References 32 publications

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“…Indeed, this has to be done in a stepwise manner since several sets of parameters enter the multistage approach 37,38 : Table 1 The FN-DMC interaction energies E (kcal/mol) obtained from various tested protocols compared to the CCSD(T)/CBS reference E R (kcal/mol). The protocol-type attribute, if applicable, is indicated in the column P. For clarity, analyzed features of the protocols with respect to the standard 26 3tJ protocol are indicated by the bold typeface.…”

Section: Analysis Of Qmc Protocolsmentioning

confidence: 99%

Quantum Monte Carlo for noncovalent interactions: an efficient protocol attaining benchmark accuracy

Dubecký

Derian

Jurečka

et al. 2014

Phys. Chem. Chem. Phys.

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Reliable theoretical predictions of noncovalent interaction energies, which are important e.g. in drug-design and hydrogenstorage applications, belong to longstanding challenges of contemporary quantum chemistry. In this respect, the fixed-node diffusion Monte Carlo (FN-DMC) is a promising alternative to the commonly used "gold standard" coupled-cluster CCSD(T)/CBS method for its benchmark accuracy and favourable scaling, in contrast to other correlated wave function approaches. This work is focused on the analysis of protocols and possible tradeoffs for FN-DMC estimations of noncovalent interaction energies and proposes an efficient yet accurate computational protocol using simplified explicit correlation terms with a favorable O(N 3 ) scaling. It achieves an excellent agreement (mean unsigned error ∼0.2 kcal/mol) with respect to the CCSD(T)/CBS data on a number of complexes, including benzene/hydrogen, T-shape benzene dimer, stacked adenine-thymine and a set of small noncovalent complexes A24. The high accuracy and reduced computational costs predestinate the reported protocol for practical interaction energy calculations of large noncovalent complexes, where the CCSD(T)/CBS is prohibitively expensive.

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Section: Analysis Of Qmc Protocolsmentioning

confidence: 99%

Quantum Monte Carlo for noncovalent interactions: an efficient protocol attaining benchmark accuracy

Dubecký

Derian

Jurečka

et al. 2014

Phys. Chem. Chem. Phys.

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“…[26,29] In addition, the HOMO/LUMO energy were estimated by O3LYP, PBE, B3LYP, and TPSSh functionals with 6-311G* basis set. [39][40][41][42][43] All the stacking motifs of studied compounds from 2 to 9 are unknown. Considering the fact that the molecular structures of our studied compounds are similar, it is rational to assume that TPB and its derivatives have similar face to face molecular packing way between the adjacent molecules.…”

Section: Computational Detailsmentioning

confidence: 99%

Theoretical Investigation on Charge Transfer Properties of 1,3,5-Tripyrrolebenzene (TPB) and its Derivatives with Electron-withdrawing Substituents

Hu¹,

Yin²,

Chaitanya³

et al. 2016

Croat. Chem. Acta

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Abstract:The electronic structures and charge transport properties of 1,3,5-tripyrrolebenzene (TPB) and its substituted derivatives with -F and -CN groups have been investigated by DFT calculations in combination with the Marcus hopping model. The dimer geometry was optimized by density functional theory method with dispersion force correction being included (DFT-D). Consequently, the charge transfer integral was evaluated. The calculation results show that the introduction of electron-withdrawing substituents does not significantly change the bond lengths and molecular symmetry of TPB, but lower the coplanarity between the pyrrole and benzene rings, especially in the case of CN substitution. Meanwhile, the introduction of electron-withdrawing groups can decrease the energy of the frontier molecular orbital and enhance the air stability. Fluorination makes the λe increase obviously while cyanation dose not. Generally speaking, the λe values of the title compounds are larger than their λh. Except for compounds 6 and 9, all others keep the face to face packing or have a slight slip in dimers, but the center of mass distances increase after fluorination or cyanation due to the distortion of the monomer's coplanarity. The predicted quasi-one-dimensional electron mobility of the dimers is up to 0.433 cm 2 ·V -1 ·s -1 at 298.15 K. The electron injection barriers of 2 and 7 are lower than that of TPB. The TPB derivatives of 1, 2, and 7 are potential n-channel materials with the high electron mobility.

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“…For example, DMC adiabatic dissociation energy of the terminal Bz-V· · · Bz-(VBz) 2 bond is ≈2.5eV, whereas it is only ≈1eV for one of the inner Bz-V-Bz· · · V· · · Bz-V-Bz bonds, see Supplementary Table VII. Given the fact that experimentally the dissociation energies of the neutrals are derived from dissociation energies measured for V n Bz + n+1 cations, corrected for kinetic shifts, using vertical metal atom and neutral complex ionization energies [18,19], the QMCcalculated adiabatic dissociation energies are expected to be more accurate than the indirectly determined experimental values [24,25].…”

Section: Resultsmentioning

confidence: 99%

Quantum Monte Carlo study of one-dimensional transition-metal organometallic cluster systems and their suitability as spin filters

et al. 2014

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We present calculations of electronic and magnetic structures of vanadium-benzene multidecker clusters VnBzn+1 (n = 1 -3) using advanced quantum Monte Carlo methods. These and related systems have been identified as prospective spin filters in spintronic applications, assuming that their ground states are half-metallic ferromagnets. Although we find that magnetic properties of these multideckers are consistent with ferromagnetic coupling, their electronic structures do not appear to be half-metallic as previously assumed. In fact, they are ferromagnetic insulators with large and broadly similar ↑-/↓-spin gaps. This makes the potential of these and related materials as spin filtering devices very limited, unless they are further modified or functionalized.

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Spin Multiplicity and Symmetry Breaking in Vanadium-Benzene Complexes

Cited by 36 publications

References 32 publications

Quantum Monte Carlo for noncovalent interactions: an efficient protocol attaining benchmark accuracy

Quantum Monte Carlo for noncovalent interactions: an efficient protocol attaining benchmark accuracy

Theoretical Investigation on Charge Transfer Properties of 1,3,5-Tripyrrolebenzene (TPB) and its Derivatives with Electron-withdrawing Substituents

Quantum Monte Carlo study of one-dimensional transition-metal organometallic cluster systems and their suitability as spin filters

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