Structure of dense hydrogen fluoride gas from neutron diffraction and molecular dynamics simulations

Kreitmeir, Markus; Heusel, Gerhard; Bertagnolli, Helmut; Tödheide, K.; Mundy, Christopher J.; Cuello, G.J.

doi:10.1063/1.1877232

Cited by 15 publications

(19 citation statements)

References 27 publications

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“…At finite temperature, however, calculations with semi-empirical potentials and simulations with purely empirical models sometimes provide results that favor cyclical structures 63,72,73,79 while others favor linear and branched clusters. 57,90 Chen and Siepmann indicated that cyclic clusters are favored for n = 3 to 6 and branched oligomers are favored for large clusters due to entropic effects. 76 In order to determine the cluster architecture, the following conventions were used here: any cluster in which every molecule has exactly two neighbors is cyclic, any cluster that has at least one molecule with three neighbors is branched (this group includes the lasso-type clusters), and every other case is considered linear.…”

Section: Aggregate Architecturementioning

confidence: 99%

“…Several groups have employed both theoretical and experimental approaches in their studies. [88][89][90] The co-existence of isolated molecules and hydrogenbonded clusters in the vapor phase has proven to be problematic for standard Monte Carlo (MC) and molecular dynamics sampling algorithms because of the energetic penalty associated with the ''evaporation'' of a molecule from a cluster and the entropic penalty associated with the addition of a monomer to a cluster. The acceptance of the standard Metropolis MC moves is based solely on the energy difference between the ''trial'' and ''old'' state; therefore, any move that destroys a hydrogen bond will most likely be rejected.…”

Section: Introductionmentioning

confidence: 99%

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First principles Monte Carlo simulations of aggregation in the vapor phase of hydrogen fluoride

McGrath

Ghogomu

Mundy

et al. 2010

Phys. Chem. Chem. Phys.

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The aggregation of hydrogen fluoride vapor is explored through the use of Monte Carlo simulations employing Kohn-Sham density functional theory with the exchange/correlation functional of Becke-Lee-Yang-Parr to describe the molecular interactions. Canonical ensemble simulations sampling the classical phase space were carried out for a system consisting of ten molecules at constant density (2700 A(3)/molecule) and at three different temperatures (T = 310, 350, and 390 K). Aggregation-volume-bias and configurational-bias Monte Carlo approaches (along with pre-sampling with an approximate potential) were employed to increase the sampling efficiency of cluster formation and destruction. A hydrogen-bond analysis shows that about two thirds of the HF molecules are part of small aggregates at 310 K, whereas only about 10% of the molecules are clustered at 390 K. As for other hydrogen-bonding systems, the size distribution exhibits some sensitivity to the criteria used to define a hydrogen bond, but the qualitative features are not affected by these differences. From the temperature dependence of the equilibrium constants, the dimer and trimer aggregation energies (not corrected for nuclear quantum effects) are estimated using a simple distance-based hydrogen-bonding criterion as -13 +/- 3 and -65 +/- 16 kJ mol(-1), respectively, whereas these binding energies are found to be somewhat different for a combined distance-angular criterion with values of -17 +/- 6 and -63 +/- 11 kJ mol(-1), respectively. The strictness of the hydrogen-bonding criterion plays a significant role for the assignment of clusters to linear, cyclic, and branched architectures with the fraction of the latter being drastically reduced for the distance-angular criterion. The average molecular dipole moment increases from 1.85 Debye for isolated molecules to about 2.0 D for dimers to about 2.75 D for larger aggregates, and the H-F bond length shows a concomitant, but smaller increase from about 0.94 to 0.98 A.

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Section: Aggregate Architecturementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

First principles Monte Carlo simulations of aggregation in the vapor phase of hydrogen fluoride

McGrath

Ghogomu

Mundy

et al. 2010

Phys. Chem. Chem. Phys.

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“…47 Because the fit is intended to extract the intramolecular structure, in reciprocal space we will focus only on the intramolecular contribution of the aforementioned q-dependent term as performed previously, [8][9][10]48,49 1…”

Section: B Fit Functionmentioning

confidence: 99%

Interplay between intramolecular and intermolecular structures of 1,1,2,2-tetrachloro-1,2-difluoroethane

et al. 2011

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We report on the interplay between the short-range order of molecules in the liquid phase of 1,1,2,2-tetrachloro-1,2-difluoroethane and the possible molecular conformations, trans and gauche. Two complementary approaches have been used to get a comprehensive picture: analysis of neutron-diffraction data by a Bayesian fit algorithm and a molecular dynamics simulation. The results of both show that the population of trans and gauche conformers in the liquid state can only correspond to the gauche conformer being more stable than the trans conformer. Distinct conformer geometries induce distinct molecular short-range orders around them, suggesting that a deep intra-and intermolecular interaction coupling is energetically favoring one of the conformers by reducing the total molecular free energy.

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“…38 This observation led to a reparameterization of the JV-P model by Pártay, Jedlovszky, and Vallauri, called PJV-P, resulting in an optimized bond length of 0.930 Å. 39 Pártay and co-workers provided an extensive comparison of the PJV-P model with several other models for liquid HF at many different states.…”

Section: Introductionmentioning

confidence: 99%

Quantum mechanical force field for hydrogen fluoride with explicit electronic polarization

Mazack

Gao

2014

The Journal of Chemical Physics

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The explicit polarization (X-Pol) theory is a fragment-based quantum chemical method that explicitly models the internal electronic polarization and intermolecular interactions of a chemical system. X-Pol theory provides a framework to construct a quantum mechanical force field, which we have extended to liquid hydrogen fluoride (HF) in this work. The parameterization, called XPHF, is built upon the same formalism introduced for the XP3P model of liquid water, which is based on the polarized molecular orbital (PMO) semiempirical quantum chemistry method and the dipole-preserving polarization consistent point charge model. We introduce a fluorine parameter set for PMO, and find good agreement for various gas-phase results of small HF clusters compared to experiments and ab initio calculations at the M06-2X/MG3S level of theory. In addition, the XPHF model shows reasonable agreement with experiments for a variety of structural and thermodynamic properties in the liquid state, including radial distribution functions, interaction energies, diffusion coefficients, and densities at various state points.

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Structure of dense hydrogen fluoride gas from neutron diffraction and molecular dynamics simulations

Cited by 15 publications

References 27 publications

First principles Monte Carlo simulations of aggregation in the vapor phase of hydrogen fluoride

First principles Monte Carlo simulations of aggregation in the vapor phase of hydrogen fluoride

Interplay between intramolecular and intermolecular structures of 1,1,2,2-tetrachloro-1,2-difluoroethane

Quantum mechanical force field for hydrogen fluoride with explicit electronic polarization

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