Binary systems from quantum cluster equilibrium theory

Brüssel, Marc; Perlt, Eva; Lehmann, Sebastian B. C.; Domaros, Michael von; Kirchner, Barbara

doi:10.1063/1.3662071

Cited by 46 publications

(69 citation statements)

References 27 publications

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“…87). Identifying criteria required to construct such a set will greatly improve the predictive power of QCE calculations.…”

Section: Discussionmentioning

confidence: 99%

“…As an alternative, we proposed fixing the QCE parameters by comparing calculated results to a single liquid phase density at ambient temperature and to the boiling point. 87 Using this procedure, it is, however, crucial to find the correct boiling point and not the temperature where a metastable phase collapses. Earlier works on pure substances, where an isobar was available, are not expected to benefit considerably from the improved QCE method.…”

Section: B Methodsological Changes To Qcementioning

confidence: 99%

“…127 Details of the QC method and other QC methods will be described elsewhere. 128 QCE calculations were performed with the Peacemaker 2.2 program package, 89 which we have recently extended to treat binary mixtures 87 and includes the methodological changes introduced above. Pressure was fixed at 101.325 kPa in all calculations, and temperature ranged from 250 to 500 K. Cluster volumes were calculated using Gepol93's solvent excluding surface algorithm 129 with van der Waals radii taken from Bondi's compilation.…”

Section: Quantum Chemical Methods and Qce Protocolmentioning

confidence: 99%

“…In an earlier QCE study on dimethylsulfoxide/water binary mixtures, 87 it was argued that a complete cluster set is not necessarily required if the employed cluster set is balanced. It was shown that the Gibbs energy of mixing depends sensitively on the relative stabilities of the neat and mixed phases.…”

Section: E Thermodynamics Of Mixingmentioning

confidence: 99%

“…Since its original proposal by Weinhold,55 this well-established model has found widespread application to neat liquids, 38, and recent advancements of the theory by our group 87 led to first investigations of binary mixtures. 87,88 We employ high-level quantum-chemical methods and pay explicit attention to the cis-trans-isomerism, which has never been incorporated into the QCE model so far. We also introduce methodological changes to the QCE procedure which are required for an accurate description of binary mixtures.…”

Section: Introductionmentioning

confidence: 99%

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Quantum cluster equilibrium model of N-methylformamide–water binary mixtures

Domaros

Jähnigen

Friedrich

et al. 2016

The Journal of Chemical Physics

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The established quantum cluster equilibrium (QCE) approach is refined and applied to Nmethylformamide (NMF) and its aqueous solution. The QCE method is split into two iterative cycles: one which converges to the liquid phase solution of the QCE equations and another which yields the gas phase. By comparing Gibbs energies, the thermodynamically stable phase at a given temperature and pressure is then chosen. The new methodology avoids metastable solutions and allows a different treatment of the mean-field interactions within the gas and liquid phases. These changes are of crucial importance for the treatment of binary mixtures. For the first time in a QCE study, the cis-trans-isomerism of a species (NMF) is explicitly considered. Cluster geometries and frequencies are calculated using density functional theory (DFT) and complementary coupled cluster single point energies are used to benchmark the DFT results. Independent of the selected quantum-chemical method, a large set of clusters is required for an accurate thermodynamic description of the binary mixture. The liquid phase of neat NMF is found to be dominated by the cyclic trans-NMF pentamer, which can be interpreted as a linear trimer that is stabilized by explicit solvation of two further NMF molecules. This cluster reflects the known hydrogen bond network preferences of neat NMF. C 2016 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license

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“…87). Identifying criteria required to construct such a set will greatly improve the predictive power of QCE calculations.…”

Section: Discussionmentioning

confidence: 99%

Section: B Methodsological Changes To Qcementioning

confidence: 99%

Section: Quantum Chemical Methods and Qce Protocolmentioning

confidence: 99%

Section: E Thermodynamics Of Mixingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Quantum cluster equilibrium model of N-methylformamide–water binary mixtures

Domaros

Jähnigen

Friedrich

et al. 2016

The Journal of Chemical Physics

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Predicting Vibrational Spectroscopy for Flexible Molecules and Molecules with Non‐Idle Environments

Kirchner

Blasius

Esser

et al. 2020

Advcd Theory and Sims

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Flexible molecules and non‐idle environments can present severe problems in the prediction of vibrational spectra. This work focuses on infrared and vibrational circular dichroism for which the latter is extremely sensitive to such complicated situations. Here two possible ways to perform spectroscopy calculations for such situations are investigated. The first approach is based on static quantum chemical calculations employing cluster‐weighting. The second approach is rooted in ab initio molecular dynamics simulations using the time correlations approach. For the present example ((R)‐butan‐2‐ol), excellent spectra from simulations are obtained for gas and bulk, when the former is averaged over trajectories with all possible starting conformers and these are scaled to match the experimental spectrum. The cluster‐weighted approach is inferior to the simulations but still reaches very good results at much less computational cost. A simplified, but computationally less expensive simulation approach is considered by approximating the electric and magnetic moments, which are input quantities in the correlation function, by classical equations and different populations analysis for the required partial charges. The results are inferior to the full simulations but still give satisfying results at the advantage of being much faster to calculate.

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Benchmarking the Computational Costs and Quality of Vibrational Spectra from Ab Initio Simulations

Taherivardanjani¹,

Elfgen²,

Reckien³

et al. 2021

Advcd Theory and Sims

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The scaling behavior of ab initio molecular dynamics simulations for the different size bulk systems of liquid methanol is presented and thereby the characteristics of every system performing on either a local compute cluster or a supercomputer are analyzed. Additionally, the influence of different parameters on the quality of the infrared and Raman spectra is investigated using different simulation frameworks, including time step, convergence criteria, density functional approximation, and basis set. Both the maximally localized Wannier functions and the radical Voronoi tessellation approaches are employed to evaluate vibrational spectra from the trajectories. The results of infrared and Raman spectra are classified in two frequency regions, 500 to 1600 cm−1 and 2500 to 4000 cm−1, in order to compare and discuss the experimental spectra and the results derived from ab initio molecular dynamics simulations comprehensively. The outcome of this study guides future experimental and theoretical researchers in order to acquire a profound perception into vibrational spectra, which evolves the way of elucidating molecular structure.

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Binary systems from quantum cluster equilibrium theory

Cited by 46 publications

References 27 publications

Quantum cluster equilibrium model of N-methylformamide–water binary mixtures

Quantum cluster equilibrium model of N-methylformamide–water binary mixtures

Predicting Vibrational Spectroscopy for Flexible Molecules and Molecules with Non‐Idle Environments

Benchmarking the Computational Costs and Quality of Vibrational Spectra from Ab Initio Simulations

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