TY - JOUR

T1 - The nano-structural inhomogeneity of dynamic hydrogen bond network of TIP4P/2005 water

AU - Belosludov, Vladimir

AU - Gets, Kirill

AU - Zhdanov, Ravil

AU - Malinovsky, Valery

AU - Bozhko, Yulia

AU - Belosludov, Rodion

AU - Surovtsev, Nikolay

AU - Subbotin, Oleg

AU - Kawazoe, Yoshiyuki

PY - 2020/4/30

Y1 - 2020/4/30

N2 - A method for studying the time dependence of the short-range molecular order of water has been proposed. In the present study, water is considered as a dynamic network between molecules at distances not exceeding 3.2 Å. The instantaneous configurations obtained with the molecular dynamics method have been sequentially analyzed. The mutual orientation of each molecule with its neighboring molecules has been studied and the interaction energy of each pair of neighbor molecules has been calculated. The majority of mutual orientation angles between molecules lie in the interval [0°; 20°]. More than 85% of the molecular pairs in each instantaneous configuration form H-bonds and the H-bond network includes all water molecules in the temperature range 233–293 K. The number of H-bonds fluctuates near the mean value and increases with decreasing temperature, and the energy of the vast majority of such bonds is much higher than the thermal energy. The interaction energy of 80% of the H-bonding molecular pairs lies in the interval [−7; −4] kcal/mol. The interaction energy of pairs that do not satisfy the H-bond angle criterion lies in the interval [−5; 4] kcal/mol; the number of such bonds does not exceed 15% and decreases with decreasing temperature. For the first time it has been found that in each instantaneous configuration the H-bond network contains built-in nanometric structural heterogeneities formed by shorter H-bonds. The fraction of molecules involved in the structural heterogeneities increases from 40% to 60% with a temperature decrease from 293 K to 233 K. Each heterogeneity has a finite lifetime and changeable structure, but they are constantly present during the entire simulation time.

AB - A method for studying the time dependence of the short-range molecular order of water has been proposed. In the present study, water is considered as a dynamic network between molecules at distances not exceeding 3.2 Å. The instantaneous configurations obtained with the molecular dynamics method have been sequentially analyzed. The mutual orientation of each molecule with its neighboring molecules has been studied and the interaction energy of each pair of neighbor molecules has been calculated. The majority of mutual orientation angles between molecules lie in the interval [0°; 20°]. More than 85% of the molecular pairs in each instantaneous configuration form H-bonds and the H-bond network includes all water molecules in the temperature range 233–293 K. The number of H-bonds fluctuates near the mean value and increases with decreasing temperature, and the energy of the vast majority of such bonds is much higher than the thermal energy. The interaction energy of 80% of the H-bonding molecular pairs lies in the interval [−7; −4] kcal/mol. The interaction energy of pairs that do not satisfy the H-bond angle criterion lies in the interval [−5; 4] kcal/mol; the number of such bonds does not exceed 15% and decreases with decreasing temperature. For the first time it has been found that in each instantaneous configuration the H-bond network contains built-in nanometric structural heterogeneities formed by shorter H-bonds. The fraction of molecules involved in the structural heterogeneities increases from 40% to 60% with a temperature decrease from 293 K to 233 K. Each heterogeneity has a finite lifetime and changeable structure, but they are constantly present during the entire simulation time.

KW - 1ST COORDINATION SHELL

KW - SMALL-ANGLE SCATTERING

KW - LIQUID WATER

KW - INFRARED-SPECTROSCOPY

KW - FLUCTUATIONS

KW - SIMULATIONS

KW - BEHAVIOR

KW - DENSITY

KW - ORIGIN

KW - H2O

UR - http://www.scopus.com/inward/record.url?scp=85084134529&partnerID=8YFLogxK

U2 - 10.1038/s41598-020-64210-1

DO - 10.1038/s41598-020-64210-1

M3 - Article

C2 - 32355196

AN - SCOPUS:85084134529

VL - 10

JO - Scientific Reports

JF - Scientific Reports

SN - 2045-2322

IS - 1

M1 - 7323

ER -