Structure of Liquid Formic Acid Investigated by First Principle and Classical Molecular Dynamics Simulations

Chelli, Riccardo; Righini, Roberto; Califano, S.

doi:10.1021/jp051731u

Cited by 27 publications

(21 citation statements)

References 57 publications

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“…Our results show that the carbonyl acceptor H-bonds are approximately one order of magnitude more occupied than the carbonyl donor H-bonds, which gives a similar trend when compared to the importance and relative strengths of these types of H-bonds previously estimated in pure liquid formic acid. 39,40 Our calculated H-bond occupancies indicate that in FA dimer structure I acceptor H-bonds give the majority of the attractive interaction between FA dimer and the water surface and, thus, are mainly responsible of the attachment of the dimers to the water surface in collisions.…”

Section: Energy Transfer In High Energy Collisionsmentioning

confidence: 87%

“…The strength of the carbonyl proton donor H-bond (Á Á ÁH-C) is only around 10% of the strongest hydrogen bonds for the pure liquid formic acid. 40 In dimer structure I, the hydroxyl donor vacancies and other carbonyl acceptor vacancies are absent, which leaves the dimer with three possible different hydrogen bonds with water. Here, the total number of available liquid water-FA dimer H-bonding sites is just six.…”

Section: Energy Transfer In High Energy Collisionsmentioning

confidence: 99%

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Ab initio molecular dynamics studies of formic acid dimer colliding with liquid water

Hänninen

Murdachaew

Nathanson

et al. 2018

Phys. Chem. Chem. Phys.

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Ab initio molecular dynamics simulations of formic acid (FA) dimer colliding with liquid water at 300 K have been performed using density functional theory. The two energetically lowest FA dimer isomers were collided with a water slab at thermal and high kinetic energies up to 68kBT. Our simulations agree with recent experimental observations of nearly a complete uptake of gas-phase FA dimer: the calculated average kinetic energy of the dimers immediately after collision is 5 ± 4% of the incoming kinetic energy, which compares well with the experimental value of 10%. Simulations support the experimental observation of no delayed desorption of FA dimers following initial adsorption. Our analysis shows that the FA dimer forms hydrogen bonds with surface water molecules, where the hydrogen bond order depends on the dimer structure, such that the most stable isomer possesses fewer FA-water hydrogen bonds than the higher energy isomer. Nevertheless, even the most stable isomer can attach to the surface through one hydrogen bond despite its reduced hydrophilicity. Our simulations further show that the probability of FA dimer dissociation is increased by high collision energies, the dimer undergoes isomerization from the higher energy to the lowest energy isomer, and concerted double-proton transfer occurs between the FA monomers. Interestingly, proton transfer appears to be driven by the release of energy arising from such isomerization, which stimulates those internal vibrational degrees of freedom that overcome the barrier of a proton transfer.

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Section: Energy Transfer In High Energy Collisionsmentioning

confidence: 87%

Section: Energy Transfer In High Energy Collisionsmentioning

confidence: 99%

Ab initio molecular dynamics studies of formic acid dimer colliding with liquid water

Hänninen

Murdachaew

Nathanson

et al. 2018

Phys. Chem. Chem. Phys.

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show abstract

“…This constitutes the focus of many of the ab initio studies on small complexes [11,12,13,14,15]. Several studies have tackled the structure of both neat acids in the liquid state (see for example Chelli et al [16] and Imberti et al [17] and references therein), but data on the aqueous system were still mostly missing (with one notable exception in Ref. [18]).…”

Section: Introductionmentioning

confidence: 99%

The hydration of formic acid and acetic acid

Soffientini

Bernasconi

Imberti

2015

Journal of Molecular Liquids

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Formic and acetic acid share the unique feature, among carboxylic acids, of crystallising in the form of long chains, containing both O-H• • •O and C-H• • •O hydrogen bonds. We have performed a neutron diffraction study of the pure acids and of three mixtures of acid and water (2:1, 1:1 and 1:2). The data from the SANDALS diffractometer at ISIS have been modelled using the Empirical Potential Structure Refinement code, which is able to reproduce a set of configurations compatible with the experimental data. The relative importance of the hydrogen bonds present in the solution is assessed based on geometrical criteria: bond length and directionality as well as number of bonds. At all concentrations, the carbonyl oxygen on the carboxylic group is the most active site for strong hydrogen bond. The tendency to establish direct interactions between acid molecules in the presence of water is reduced for acetic acid by a larger degree than for formic acid. The overall tendency is for a greater number of hydrogen bonds being formed when the solution is more diluted. The availability of good quality structural data on the liquid states is of great importance for the understanding of spectroscopic experiments and for benchmarking both classic molecular dynamics and ab initio simulations. The results provide a springboard to more realistic models of aerosol formation, which is greatly needed for better understanding of clouds formation processes.

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“…In the liquid phase, recent firstprinciples and classical molecular dynamics simulations 4,5 suggest the presence of large branched structures which consist of small clusters characterized by strong O-H · · · O H-bonds, which are held together by a weak C-H · · · O type of interaction. The population of the cyclic dimer configuration, which dominates in the gas phase, has been estimated to be 23%.…”

Section: Introductionmentioning

confidence: 99%

Formic Acid Dimerization: Evidence for Species Diversity from First Principles Simulations

Rodziewicz

Doltsinis

2009

J. Phys. Chem. A

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Dimerization of formic acid has been simulated using ab initio molecular dynamics at conditions mimicking rare gas matrix isolation experiments. Aggregation product distributions and the corresponding reaction pathways have been studied as a function of temperature. At higher temperatures, the cyclic, C(2h) symmetric, global minimum structure A with two O-H...O horizontal lineC hydrogen bonds predominates over the second most stable, acyclic, local minimum isomer B with one O-H...O horizontal lineC and one C-H...O horizontal lineC hydrogen bond, whereas the latter is the main species at low temperature. Significant concentrations of two additional, less stable, local minimum species, C exhibiting an O-H...O horizontal lineC and an O-H...O(H)-C hydrogen bond, and D with an O-H...O(H)-C and a C-H...O horizontal lineC hydrogen bond, which should be detectable in experiment, are predicted at low temperature. Theoretical vibrational spectra are provided to guide the experimental search for these species. Furthermore, free-energy barriers for thermal interconversion of different dimer species have been calculated using targeted molecular dynamics in conjunction with thermodynamic integration. The small barrier for the C --> A reaction of 7.0 kJ/mol indicates that the C species can only be stabilized at ultracold conditions. The data presented here thus hold important clues for the execution and interpretation of low-temperature vibrational spectroscopy at matrix isolation or ultracold helium droplet conditions.

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Structure of Liquid Formic Acid Investigated by First Principle and Classical Molecular Dynamics Simulations

Cited by 27 publications

References 57 publications

Ab initio molecular dynamics studies of formic acid dimer colliding with liquid water

Ab initio molecular dynamics studies of formic acid dimer colliding with liquid water

The hydration of formic acid and acetic acid

Formic Acid Dimerization: Evidence for Species Diversity from First Principles Simulations

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