中国物理B ›› 2018, Vol. 27 ›› Issue (8): 83103-083103.doi: 10.1088/1674-1056/27/8/083103

• ATOMIC AND MOLECULAR PHYSICS • 上一篇    下一篇

A simulation study of water property changes using geometrical alteration in SPC/E

Ming-Ru Li(李明儒), Nan Zhang(张楠), Feng-Shou Zhang(张丰收)   

  1. 1 Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education of China and College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875, China;
    2 Beijing Radiation Center, Beijing 100875, China;
    3 Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator of Lanzhou, Lanzhou 730000, China
  • 收稿日期:2018-04-03 修回日期:2018-05-15 出版日期:2018-08-05 发布日期:2018-08-05
  • 通讯作者: Feng-Shou Zhang E-mail:fszhang@bnu.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 11635003, 11025524, and 11161130520), the National Basic Research Program of China (Grant No. 2010CB832903), and the European Commission's 7th Framework Programme (Fp7-PEOPLE-2010-IRSES) (Grant Agreement Project No. 269131).

A simulation study of water property changes using geometrical alteration in SPC/E

Ming-Ru Li(李明儒)1,2, Nan Zhang(张楠)1,2, Feng-Shou Zhang(张丰收)1,2,3   

  1. 1 Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education of China and College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875, China;
    2 Beijing Radiation Center, Beijing 100875, China;
    3 Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator of Lanzhou, Lanzhou 730000, China
  • Received:2018-04-03 Revised:2018-05-15 Online:2018-08-05 Published:2018-08-05
  • Contact: Feng-Shou Zhang E-mail:fszhang@bnu.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 11635003, 11025524, and 11161130520), the National Basic Research Program of China (Grant No. 2010CB832903), and the European Commission's 7th Framework Programme (Fp7-PEOPLE-2010-IRSES) (Grant Agreement Project No. 269131).

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摘要： We present a systematic investigation of the impact of changing the geometry structure of the SPC/E water model by performing a series of molecular dynamic simulations at 1 bar (1 bar=105 Pa) and 298.15 K. The geometric modification includes altering the H-O-H angle range from 90° to 115° and modifying the O-H length range from 0.90 Å to 1.10 Å in the SPC/E model. The former is achieved by keeping the dipole moment constant by modifying the O-H length, while in the latter only the O-H length is changed. With the larger bond length and angle, we find that the liquid shows a strong quadrupole interaction and high tetrahedral structure order parameter, resulting in the enhancement of the network structure of the liquid. When the bond length or angle is reduced, the hydrogen bond lifetime and self-diffusion constant decrease due to the weakening of the intermolecular interaction. We find that modifying the water molecular bond length leading to the variation of the intermolecular interaction strength is more intensive than changing the bond angle. Through calculating the average reduced density gradient and thermal fluctuation index, it is found that the scope of vdW interaction with neighbouring water molecules is inversely proportional to the change of the bond length and angle. The effect is mainly due to a significant change of the hydrogen bond network. To study the effect of water models as a solvent whose geometry has been modified, the solutions of ions in different solvent environments are examined by introducing NaCl. During the dissolving process, NaCl ions are ideally dissolved in SPC/E water and bond with natural water more easily than with other solvent models.

关键词: molecular dynamics simulation, geometric modification, intermolecular interaction, ion', s solvation

Abstract: We present a systematic investigation of the impact of changing the geometry structure of the SPC/E water model by performing a series of molecular dynamic simulations at 1 bar (1 bar=105 Pa) and 298.15 K. The geometric modification includes altering the H-O-H angle range from 90° to 115° and modifying the O-H length range from 0.90 Å to 1.10 Å in the SPC/E model. The former is achieved by keeping the dipole moment constant by modifying the O-H length, while in the latter only the O-H length is changed. With the larger bond length and angle, we find that the liquid shows a strong quadrupole interaction and high tetrahedral structure order parameter, resulting in the enhancement of the network structure of the liquid. When the bond length or angle is reduced, the hydrogen bond lifetime and self-diffusion constant decrease due to the weakening of the intermolecular interaction. We find that modifying the water molecular bond length leading to the variation of the intermolecular interaction strength is more intensive than changing the bond angle. Through calculating the average reduced density gradient and thermal fluctuation index, it is found that the scope of vdW interaction with neighbouring water molecules is inversely proportional to the change of the bond length and angle. The effect is mainly due to a significant change of the hydrogen bond network. To study the effect of water models as a solvent whose geometry has been modified, the solutions of ions in different solvent environments are examined by introducing NaCl. During the dissolving process, NaCl ions are ideally dissolved in SPC/E water and bond with natural water more easily than with other solvent models.

Key words: molecular dynamics simulation, geometric modification, intermolecular interaction, ion's solvation

中图分类号:  (Molecular dynamics and other numerical methods)

  • 31.15.xv
31.70.-f (Effects of atomic and molecular interactions on electronic structure) 61.25.Em (Molecular liquids)