Effects of liquefied gas temperature and negative pressure on the microstructural characteristics of oxide Mg2SiO4 using molecular dynamics simulation method

• Published in: Computational materials science Vol. 242; p. 113075
• Main Authors: Tran Quoc, Tuan, Nguyen Trong, Dung, Cao Long, Van, Pham Huu, Kien, Ţălu, Ştefan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.06.2024
• Subjects: Liquefied gas temperature; Microstructure; Molecular dynamics; Negative pressure; oxide Mg2SiO4; Molecular dynamics; Negative pressure; Microstructure; Liquefied gas temperature; oxide Mg2SiO4
• ISSN: 0927-0256; 1879-0801
• DOI: 10.1016/j.commatsci.2024.113075

[Display omitted] •The obtained results show that using the Oganov pair interaction force field is appropriate.•At a temperature of 300 K and a pressure of 0 GPa, the length of links Si-O is 1.58 Å, O-O is 2.58 Å, Si-Mg is 3.18 Å, Mg-O is 1.96 Å, Mg- Mg is 2.88 Å.•When the temperature decreases to the liquefied gas temperature, the Si-O and Mg-O have a constant value while Si-Mg decreases to 3.12 Å.•When the pressure decreases to −2, −4, −6GPa, Si-O has a constant value, Si-Mg increases to 3.18 Å and Mg-O increases to 1.98 Å.•The bond angles of SiO4 and SiO5 are almost unchanged, with MgO3, MgO4, MgO5, MgO6, MgO7 disappearing at pressure −6 GPa and temperature 77 K.•The relationship between temperature and total energy of the system is determined to be a straight line with liquefied gas temperature and a quadratic curve with negative pressure. Our study focused on examining the behavior of oxide Mg2SiO4 under various liquefied gas temperatures, including 4.22 K (Helium), 77 K (Nitrogen), 83.88 K (Argon), 90 K (Oxygen), 194.3 K (Carbon), and 300 K (room temperature), while maintaining a pressure of 0 GPa. Additionally, we explored the effects of pressures ranging from 0 to −6 GPa at a temperature of 77 K using first principles molecular dynamics simulations. Our findings indicate significant variations in the system’s size, energy, and the lengths of Si-Si, Si-O, O-O, Si-Mg, Mg-O, and Mg-Mg bonds with decreasing temperature at 0 GPa and decreasing pressure at a temperature of 77 K. Moreover, substantial variations were observed in the average coordination number of bonds, the quantity of SiOx, MgOy structural units (where x  = 4, 5 and y = 3, 4, 5, 6, 7), and bond angles of Si-O-Si, and Mg-O-Mg under negative pressure while remaining relatively constant across liquefied gas temperatures. Furthermore, we successfully established a linear relationship between temperature, pressure, and the total energy of the system. These insights into the behavior of oxide Mg2SiO4 serve as valuable groundwork for future experimental investigations, particularly in leveraging the material’s potential applications in advanced technological fields.