ISSN 0021-8944, Journal of Applied Mechanics and Technical Physics, 2018, Vol. 59, No. 1, pp. 41–51.
Pleiades Publishing, Ltd., 2018.
Original Russian Text
V.E. Zalizniak, O.A. Zolotov, I.I. Ryzhkov.
EFFECTIVE MOLECULAR DYNAMICS MODEL OF IONIC SOLUTIONS
FOR LARGE-SCALE CALCULATIONS
V. E. Zalizniak
, and I. I. Ryzhkov
Abstract: A model of ionic solutions is proposed which can be used to calculate aqueous salt solu-
tions in diﬀerent nanostructures. The interaction potential of the model includes the Lennard-Jones
potential and angularly averaged dipole–dipole and ion–dipole interactions. Lennard-Jones poten-
tial parameters for diﬀerent ions are obtained. Characteristics of aqueous solutions at diﬀerent salt
concentrations are calculated using the molecular dynamics method. It is shown that the calculated
values of the hydration shells of ions parameters are in good agreement with the theoretical and
experimental data at a salt concentration of 1 mol/kg. The computational scheme used in the calcu-
lations is described. It is shown that calculations using the proposed model require less computing
resources compared with the standard models of ionic solutions.
Keywords: ionic solution, interaction potential, molecular dynamics.
Aqueous solutions comprising ions are often used in electrochemical processes and technologies of water
desalination. High concentrations of ions dissolved in water are contained in living organisms, and their presence
can inﬂuence the functioning of living cells. The structure and dynamics of the hydration shells of ion have a
signiﬁcant eﬀect on chemical reactions involving metal ions in solution.
The molecular dynamics method is widely used to determine the characteristics of aqueous ionic solutions.
Selecting a correct and eﬀective interaction potential is of great importance in molecular dynamics simulations. Pair
potentials are often used. Interaction of ions is described by the sum of two potentials: the Lennard-Jones potential
and the electrostatic potential, i.e., the ions are considered charged Lennard-Jones particles. Water molecules are
usually described using diﬀerent multi-site models [1–5]. At each site, a partial charge is speciﬁed such that the
sum of the positive and negative charges is zero. It is assumed that the relative position of the sites does not change
with time. All sites of one water molecule electrostatically interact with the sites of the other water molecules.
Interaction of water molecules is described by the Lennard-Jones potential. Model parameters are selected so as to
reproduce diﬀerent properties of water.
Computational costs for modeling ionic solutions increase with increasing number of sites in the water model.
The time of calculation of pairwise interactions is approximately proportional to the square of the number of these
sites. In addition, it is necessary to calculate the long-range interaction of charges using the particle–particle–
particle–mesh method  or the particle–Ewald mesh method [7, 8]. These methods are based on the fast Fourier
transform and include O(N log N)operations(N is the number of atoms).
Institute of Mathematics and Fundamental Informatics, Siberian Federal University, Krasnoyarsk, 660041
Russia; firstname.lastname@example.org; ozolot
Institute of Computational Modeling, Siberian Branch, Russian
Academy of Sciences, Krasnoyarsk, 660036 Russia; email@example.com. Translated from Prikladnaya Mekhanika i
Tekhnicheskaya Fizika, Vol. 59, No. 1, pp. 49–60, January–February, 2018. Original article submitted September 1,
2016; revision submitted November 22, 2016.
2018 by Pleiades Publishing, Ltd.