q-exponential distribution in time correlation function of water hydrogen bonds

Campo, M. G.; Ferri, Gustavo Luis; Roston, Graciela B.

doi:10.1590/s0103-97332009000400017

Cited by 5 publications

(6 citation statements)

References 29 publications

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“…In a previous work, we found a q-exponential behavior in P (t), in which q increases with T −1 approximately below 300 K. q(T ) is also correlated with the probability of occurrence of four hydrogen bonds, and the subdiffusive motion of the water molecules [28].…”

Section: Introductionmentioning

confidence: 70%

Structural and dynamic properties of SPC/E water

Campo

2010

Pap. Phys.

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I have investigated the structural and dynamic properties of water by performing a series of molecular dynamic simulations in the range of temperatures from 213 K to 360 K, using the Simple Point Charge-Extended (SPC/E) model. I performed isobaric-isothermal simulations (1 bar) of 1185 water molecules using the GROMACS package. I quantified the structural properties using the oxygen-oxygen radial distribution functions, order parameters, and the hydrogen bond distribution functions, whereas, to analyze the dynamic properties I studied the behavior of the history-dependent bond correlation functions and the non-Gaussian parameter α2(t) of the mean square displacement of water molecules. When the temperature decreases, the translational (τ ) and orientational (Q) order parameters are linearly correlated, and both increase indicating an increasing structural order in the systems. The probability of occurrence of four hydrogen bonds and Q both have a reciprocal dependence with T , though the analysis of the hydrogen bond distributions permits to describe the changes in the dynamics and structure of water more reliably. Thus, an increase on the caging effect and the occurrence of long-time hydrogen bonds occur below ∼ 293 K, in the range of temperatures in which predominates a four hydrogen bond structure in the system.

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Section: Introductionmentioning

confidence: 70%

Structural and dynamic properties of SPC/E water

Campo

2010

Pap. Phys.

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“…(1) has been employed in a growing number of theoretical and empirical works on a large variety of themes. Examples include scale-free networks [10][11][12][13][14], dynamical systems [15][16][17][18][19][20][21][22][23][24][25][26][27], algebraic structures [28][29][30][31] among other topics in statistical physcics [32][33][34][35][36].…”

Section: Q-exponential Distributionmentioning

confidence: 99%

q-distributions in complex systems: a brief review

Picoli¹,

Mendes²,

Malacarne³

et al. 2009

Braz. J. Phys.

103

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The nonextensive statistical mechanics proposed by Tsallis is today an intense and growing research field. Probability distributions which emerges from the nonextensive formalism (q-distributions) have been applied to an impressive variety of problems. In particular, the role of q-distributions in the interdisciplinary field of complex systems has been expanding. Here, we make a brief review of q-exponential, q-Gaussian and q-Weibull distributions focusing some of their basic properties and recent applications. The richness of systems analyzed may indicate future directions in this field.

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“…As is expected, the average structural behavior of the water molecules in the simulation system at infinite dilution is not affected by what occurs around QU. Both RDFs of OW around OW and HBs between water molecules distribution are the expected for SPC/E water model at the values of the thermodynamics variables [69,96,110]. However, when the concentration of QU increases and aggregates are formed, there is a decrease in the formation of HBs and the gradual breakdown of the tetrahedral structure of water on average throughout the simulated system.…”

Section: Discussionmentioning

confidence: 57%

“…So, both D eff (t) of systems II and III have values smaller than that of system I, and they have an asymptotic decay for large M(t)s. The QU aggregates of systems II and III, which impede the random displacement of water molecules, produce this change in the behavior of the D eff (t) with increasing QU concentration. It is an incipient subdiffusive behavior already observed in simulated systems such as, among others, water molecules confined in soft environments [86] and subcooled water [110]. Water molecules have a caging behavior remaining temporarily trapped in regions located between aggregates under a subdiffusive regime because the possibility of random movement decreases significantly.…”

Section: Discussionmentioning

confidence: 82%

Structural, dynamic, and hydration properties of quercetin and its aggregates in solution

Campo¹,

Corral²

2022

J. Phys.: Condens. Matter

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Quercetin is a flavonoid present in the human diet with multiple health benefits. Quercetin solutions are inhomogeneous even at very low concentrations due to quercetin's tendency to aggregate. We simulate, using molecular dynamics, three systems of quercetin solutions: infinite dilution, 0.22 M, and 0.46 M. The systems at the two highest concentrations represent regions of the quercetin aggregates, in which the concentration of this molecule is unusually high. We study the behavior of this molecule, its aggregates, and the modifications in the surrounding water. In the first three successive layers of quercetin hydration, the density of water and the hydrogen bonds formations between water molecules are smaller than that of bulk. Quercetin has a hydrophilic surface region that preferentially establishes donor hydrogen bonds with water molecules with relative frequencies from 0.12 to 0.46 at infinite dilution. Also, it has two hydrophobic regions above and below the planes of its rings, whose first hydration layers are further out from quercetin ($ \approx 0.3 \: \textup{\r{A}}$) and their water molecules do not establish hydrogen bonds with it. Water density around the hydrophobic regions is smaller than that of the hydrophilic. Quercetin molecules aggregate in $\pi$-stacking configurations, with a distance of $\approx 0.37$ nm between the planes of their rings, and form bonds between their hydroxyl groups. The formation of quercetin aggregates decreases the hydrogen bonds between quercetin and the surrounding water and produces a subdiffusive behavior in water molecules. Quercetin has a subdiffusive behavior even at infinite dilution, which increases with the number of molecules within the aggregates and the time they remain within them.

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q-exponential distribution in time correlation function of water hydrogen bonds

Cited by 5 publications

References 29 publications

Structural and dynamic properties of SPC/E water

Structural and dynamic properties of SPC/E water

q-distributions in complex systems: a brief review

Structural, dynamic, and hydration properties of quercetin and its aggregates in solution

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