Ground and excited electronic states of azobenzene: A quantum Monte Carlo study

Dubecký, Matúš; Derian, René; Mitáš, Luboš; Štich, Ivan

doi:10.1063/1.3506028

Cited by 37 publications

(50 citation statements)

References 39 publications

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“…Since the concept of error cancellation is not limited to one determinant, similar behaviour is expected in case of noncovalent interactions between open-shell systems where completeactive-space wave functions capturing multi-reference effects 41,42 may be used instead of Hartree-Fock/Kohn-Sham determinants.…”

Section: Orbitals In the Slater Part Of ψ Tmentioning

confidence: 86%

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: Orbitals In the Slater Part Of ψ Tmentioning

confidence: 86%

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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“…[69,70] Beispielsweise kçnnen angeregte Zustände mit verschiedenen Va rianten des stochastischen Quanten-Monte-Carlo-Verfahrens (QMC) [71,72] oder dessen Kombinationen mit anderen Te chniken [73,74] berechnet werden. Beispiele fürA nwendungen sind Azobenzol, [75] Festkçrper [76] oder Modelle fürd en Chromophor von Retinal. [77] Eine sehr interessante Abwandlung des QMC-Verfahrens ist die so genannte Full-CI-Quanten-Monte-Carlo-Methode (FCIQMC), [78,79] bei der ein Determinanten-basiertes FCI-Problem nicht wie üblich mithilfe der Speicherung aller Koeffizienten gelçst wird, sondern ein stochastischer Algorithmus nach und nach die wichtigsten Determinanten besucht.…”

Section: Multi-konfigurations-und Multi-referenz-methodenunclassified

Molekulare Photochemie: Moderne Entwicklungen in der theoretischen Chemie

Mai

González

2020

Angewandte Chemie

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Photochemie ist ein faszinierendes Teilgebiet der Chemie, das sich mit der Wechselwirkung von Molekülen und Licht befasst. Die Simulation von lichtinduzierten Prozessen spielt auch in anderen Forschungsgebieten wie Biologie, Materialwissenschaften oder Medizin eine bedeutende Rolle. Dieser Kurzaufsatz beleuchtet die jüngsten Entwicklungen in der theoretischen Chemie, die das Ziel haben, experimentelle Genauigkeit bei der Berechnung von elektronisch angeregten Zuständen von Molekülen und bei der Simulation von deren lichtinduzierten Dynamiken zu erreichen. Wir konzentrieren uns dabei auf neue, aufstrebende Methoden und zeigen ausgewählte Beispiele, welche die Fortschritte der letzten Jahre für folgende Themen aufzeigen: die Voraussage komplexer Elektronenstrukturen mit starker Korrelation, die Berechnung von großen Molekülen, die Beschreibung von multi‐chromophorischen Systemen und die Simulation nicht‐adiabatischer Moleküldynamik auf langen Zeitskalen; dies umfasst Moleküle sowohl in der Gasphase als auch in komplexer biologischer Umgebung.

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“…The many-body study revealed deviations from experiments by as much as ≈1 eV with DFT techniques and even with medium-quality quantum chemistry methods [53,54], depending on the level of correlation and/or basis set used. However, these differences affect mostly the singlet/triplet excited states of the molecule [54], rather than the states around the Fermi level responsible for the conductance of the contacted molecule which are very similar for both isomers.…”

Section: Discussionmentioning

confidence: 99%

Rigidity of the conductance of an anchored dithioazobenzene optomechanical switch

2013

Self Cite

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Reversible opto-mechanical molecular switch based on a single azobenzene molecule suspended via thiolate links between realistic models of gold tips is investigated. Using a combination of the transfer matrix technique and density functional theory we focus on conductance of the nano-device in the two (meta)stable cis and trans junction conformations. We find the conductance of both conformations to be broadly similar. In qualitative agreement with related experiments, we find that the same nano-device with one/two methylene linker group(s) inserted on one/both ends of the azobenzene molecule is driven into tunneling regime and reduces the conductances by up to two orders of magnitude, again almost uniformly for both conformations. These results clarify the huge differences in switching ratios found previously and indicate that this nano-device is not particularly suited for use as a molecular switch based on conductance change.

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Ground and excited electronic states of azobenzene: A quantum Monte Carlo study

Cited by 37 publications

References 39 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

Molekulare Photochemie: Moderne Entwicklungen in der theoretischen Chemie

Rigidity of the conductance of an anchored dithioazobenzene optomechanical switch

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