An analysis of stationary points on the (HF) n potential surfaces ( n ≤6) predicted by the diatomics-in-ionic-systems model

Grigorenko, Bella L.; Moskovsky, Alexander; Nemukhin, Alexander V.

doi:10.1016/s0166-1280(99)00211-0

Cited by 6 publications

(7 citation statements)

References 25 publications

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“…37 Most recently, cyclic oligomers were seen as the dominating species for up to n = 8 at low pressures. 39,125 It is generally agreed that the cyclic isomers represent the global energy minimum of a given cluster size (a view supported by electronic structure calculations 48,58,59 and other models 64,66,67 ). 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.…”

Section: Aggregate Architecturementioning

confidence: 91%

“…[40][41][42] Theoretical studies have computed the structures, energies, and vibrational frequencies of the dimer, 1,2,4,8,[43][44][45][46][47] trimer, 6,[48][49][50][51][52] and larger clusters 7,[53][54][55][56][57][58][59][60][61][62] using static quantum chemical methods. Clusters have also been explored with semi-empirical methods and methods based on molecular mechanics force field, [63][64][65][66][67] including analytical potential energy surfaces fit to ab initio data to compute the frequencies. [68][69][70][71] Approaches based on statistical mechanics (including particle-based simulation [72][73][74][75][76][77][78][79][80][81] ) have bee...…”

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: 91%

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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“…There have been numerous calculations of the structures and relative energies of various isomers of the (HF) n complexes. − Unfortunately, vibrational frequencies have only been reported for some of these, and the VTMAs needed in the present study have not been reported. As a result, we carried out ab initio MP2 calculations for a number of the important species using a 6-311++G(3df,3pd) basis set .…”

Section: Methodsmentioning

confidence: 99%

“…The band at 3878.0 cm -1 is so weak that an accurate determination of the associated cluster size was not possible. A number of “4 + 2” structures are indeed local minima on the (HF) 6 potential energy surface, , and ab initio calculations are underway in an effort to assign these bands.…”

Section: Determination Of Vibrational Transition Dipole Moment Anglesmentioning

confidence: 99%

“…It is now well established, from both experiment − and theory, − that the most stable isomers of the larger polymers of HF are all cyclic, at least up to n = 7. A recent combined experimental/theoretical study of the H−F out-of-plane libration fundamental band of the tetramer provided conclusive evidence for its cyclic structure .…”

Section: Introductionmentioning

confidence: 99%

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The Growth of HF Polymers in Helium Nanodroplets: Probing the Barriers to Ring Insertion

Douberly

Miller

2003

J. Phys. Chem. B

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We report the first experimental observation of (HF) n (n ) 4,5,6) clusters, grown in helium nanodroplets. The structures of these complexes are determined from infrared laser spectroscopy, recorded in the spectral region from 3100 to 3900 cm -1 . Comparisons with previous gas-phase spectra and ab initio calculations indicate that the helium-solvated tetramer is cyclic, suggesting that the barrier to inserting an HF into a preformed cyclic trimer is small. In contrast, the cyclic pentamer is not observed. Instead, we observe four of the five H-F stretching vibrational bands of a new isomer of (HF) 5 , corresponding to a tetramer ring to which a fifth HF is hydrogen bonded. A large static electric field is used to establish that this (HF) 5 isomer is indeed polar and to measure the angle between the permanent dipole moment and the transition dipole moments for these vibrations. These vibrational transition dipole moment angles (VTMAs) and the corresponding vibrational frequencies are also calculated at the MP2/6-311++G(3df,3pd) level of theory. Comparisons between the experimental and calculated VTMAs and the vibrational frequencies provide convincing evidence for the formation of this "4 + 1" isomer. The results are rationalized in terms of the available intermolecular potentials for these systems.

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Sequential growth simulation of (NH3)n clusters (n=2–8) in ultracold superfluid environment

Patrone

Mella

2011

Chemical Physics Letters

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An analysis of stationary points on the (HF) n potential surfaces ( n ≤6) predicted by the diatomics-in-ionic-systems model

Cited by 6 publications

References 25 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

The Growth of HF Polymers in Helium Nanodroplets: Probing the Barriers to Ring Insertion

Sequential growth simulation of (NH3)n clusters (n=2–8) in ultracold superfluid environment

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