TY - JOUR

T1 - Statistical geometry characterization of local structure of TMAO, TBA and urea aqueous solutions

AU - Kadtsyn, E. D.

AU - Anikeenko, A. V.

AU - Medvedev, N. N.

PY - 2019/7/15

Y1 - 2019/7/15

N2 - Recently, we have revealed that trimethylamine-N-oxide (TMAO) molecules in aqueous solutions are distributed generally like random spheres in space (A.V. Anikeenko et al. J. Mol. Liq. 245 (2017) 35–41). We have shown that the variance of the distribution of Voronoi region volumes for the TMAO molecules and the hard random spheres are identical at the corresponding concentrations up to the mole fraction x ~ 0.1 (or packing fraction η ~ 0.2). In the current work, we study clusters in TMAO solutions and calculate the weighted mean cluster size and some topological cluster characteristics. For all these parameters, a great matching of TMAO and random spheres is also observed. The same analysis for tert-butyl alcohol (TBA) and urea aqueous solutions is carried out. These molecules have a tendency to cluster even at very low concentrations. However, basic geometrical features of the clusters are the same both for solutions and for the system of random spheres, indicating that geometrical laws governing the allocation of non-overlapping spheres in space should be taken into account when describing the structure of solutions even at rather low concentrations.

AB - Recently, we have revealed that trimethylamine-N-oxide (TMAO) molecules in aqueous solutions are distributed generally like random spheres in space (A.V. Anikeenko et al. J. Mol. Liq. 245 (2017) 35–41). We have shown that the variance of the distribution of Voronoi region volumes for the TMAO molecules and the hard random spheres are identical at the corresponding concentrations up to the mole fraction x ~ 0.1 (or packing fraction η ~ 0.2). In the current work, we study clusters in TMAO solutions and calculate the weighted mean cluster size and some topological cluster characteristics. For all these parameters, a great matching of TMAO and random spheres is also observed. The same analysis for tert-butyl alcohol (TBA) and urea aqueous solutions is carried out. These molecules have a tendency to cluster even at very low concentrations. However, basic geometrical features of the clusters are the same both for solutions and for the system of random spheres, indicating that geometrical laws governing the allocation of non-overlapping spheres in space should be taken into account when describing the structure of solutions even at rather low concentrations.

KW - MOLECULAR-DYNAMICS SIMULATION

KW - CONTINUUM-PERCOLATION

KW - VOLUMETRIC PROPERTIES

KW - HEAT-CAPACITIES

KW - FORCE-FIELD

KW - MIXTURES

KW - WATER

KW - DENSITY

KW - MODEL

UR - http://www.scopus.com/inward/record.url?scp=85065182945&partnerID=8YFLogxK

U2 - 10.1016/j.molliq.2019.04.147

DO - 10.1016/j.molliq.2019.04.147

M3 - Article

AN - SCOPUS:85065182945

VL - 286

JO - Journal of Molecular Liquids

JF - Journal of Molecular Liquids

SN - 0167-7322

M1 - 110870

ER -