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Study on diffusion behavior of water molecules in mineral and vegetable oil
Published in Ahmad Safuan Bin A Rashid, Junwen Zhang, Advances in Mineral Resources, Geotechnology and Geological Exploration, 2023
Qingdong Zhu, Ran Xu, Wenbing Zhu, Haozhe Wang, Zhaoliang Gu, Mengzhao Zhu
The interactions between water molecules and oil molecules can be obtained by Equation (2), as shown below:Einter=Etotal−Ew+Eo where Einter is the interaction energy between water molecules and oil molecules in our model; Etotal, Ew, and E0 represent the total potential energy of the oil-water model, the potential energy of water, and the potential energy of oil, respectively. The calculated interaction energy between water molecules and vegetable/mineral oil molecules is presented in Table 3. Positive interaction energy indicates a repulsive force between molecules; While negative interaction energy indicates an attractive force between molecules. The absolute value of interaction energy reflects the force strength between molecules.
The effect of ionisation of silica nanoparticles on their binding to nonionic surfactants in oil–water system: an atomistic molecular dynamic study
Published in Molecular Physics, 2018
Parul Katiyar, Jayant K. Singh
The interaction energy between two atoms is expressed as a sum of bonded and nonbonded terms. The nonbonded interaction includes Lennard-Jones and electrostatic interactions as described by Equation (1). where ϵ, σ, r, qi, qj and ϵo are the energy well depth, closest distance of approach, distance between the two particles, charges on particle i and j and permittivity of free space, respectively. All the nonbonded interaction parameters are given in Table 1. The bonded interactions include bonds, angles and dihedrals as given in Equation (2). Contribution of each term in Equation (2) is described in Equations (3)–(6). ro and θo are the equilibrium bond distance and equilibrium angle, respectively. In Equations (5) and (6) we have defined two different formulas for dihedral. All the dihedrals are defined using one of the two formulas as mentioned in Table 2. All the bonded force field parameters are given in Table 2.
A convenient and accurate wide-range parameter relationship between Buckingham and Morse potential energy functions
Published in Molecular Physics, 2018
Teik-Cheng Lim, James Alexander Dawson
The computation of elastic behaviour, fluid dynamics, mass transfer, heat flow and other physical properties at the molecular scale requires molecular modelling [1–3] by means of either Monte Carlo [4–6] or molecular dynamics [7–9] approaches. For both approaches, the interaction energy between bonded and non-bonded atoms and between molecules can be conveniently quantified by potential energy functions. While the quantum mechanical approach is theoretically more rigorous, semi-empirical potential energy functions are attractive due to their convenient applications, especially when dealing with many-body problems – the reader is referred to Varshni [10], Erkoc [11] and Palmo et al. [12] for in-depth reviews of potential energy functions. In fact, it has been noted by Murrell et al. [13] that simple diatomic functions, such as the Morse, Rydberg and Born–Mayer functional forms, give a qualitatively correct description of the potential energy and only modest extensions are needed to obtain functions that stand up to the most stringent experimental tests. This remark continues to be true to this day (e.g. [14–17]). The Morse potential and other well-known diatomic potentials are widely applied in molecular simulations , including investigations of the thermodynamic properties of molecule systems and the fractionation of isotopes [18–22].
Combined experimental and computational studies on molecular structure of nickel complex of 4-amino-N-(1, 3-thiazol-2-yl) benzenesulfonamide with coordinated pyridine
Published in Inorganic and Nano-Metal Chemistry, 2021
Sachin B. Pandya, Bhavesh N. Socha, Kaushik P. Chaudhary, Rahul P. Dubey, Bhavin R. Chavda, Urmila H. Patel, Maheshkumar K. Patel, Nikita J. Patel, Bhupesh S. Bhatt
Hirshfeld surface (HS) analysis is employed to study the strength of the intermolecular contacts of the molecule.[46] The shape index and curvedness plots are significant pointers for the C-H…π and π…π stacking interactions, respectively. The pair of triangles (blue and red) for the shape index and the curvedness surfaces presentation broad, relatively flat regions are characteristics of π…π interactions of the molecule. The 2D fingerprint plots can be built to focus on particular atom pair contacts. The percentages contributions of H…H (61%), C…H (19%), O…H (10%) and N…H (10%) contacts of Ni-STZ molecule are revealing the value of H…H interactions are higher among all the interactions. There are four different types of energies like interaction energy namely repulsion, dispersion, electrostatic and polarization energy. Repulsion energy is related with the overlap of occupied orbitals. Dispersion and coulombic interactions are long range interactions. The interaction energies for Ni-STZ complex have been calculated using Crystal Explorer 17.5 program and the outcomes are presented in Table 5 (energies are in kJ mol−1). Various symmetry molecular pairs in each cluster are specified by different color codes (Figure 8). The Ni-STZ complex, neighboring molecules are present within a distance of 3.8 Å from the molecule in the asymmetric unit.[47,48] The red-colored molecule (symmetry code: x, y, z) located at a distance of 9.79 Å (centroid-centroid distance of the two molecules) has shown the highest dispersion interaction energy of −47.3 kJ mol−1 and also shows the highest electrostatic interaction energy of −9.3 kJ mol−1 due to C-H…O and N-H…O/N interactions present in the molecule. The lowest dispersion and electrostatic interaction energy {symmetry code: –x + 1/2, y + 1/2, –z + 1/2 (purple colored); R = 11.56 Å} is found to be −21.0 and −8.1 kJ mol−1, respectively. The energy calculation points out that interaction in crystals is dominated by dispersion energy framework for the Ni-STZ complex. The energy values suggest the complex is energetically more stable. The result also founds that the chelation with metal develops actively stable molecules.