STATISTICAL RESEARCH OF DENSITY FIELD FLUCTUATIONS IN SPHERICAL MOLECULAR NANOPARTICLES

UDC 531.19;538.911

 

Narkevich Ivan Ivanovich − DSc (Physics and Mathematics), Professor, Professor, the Department of Physics. Belarusian State Technological University (13a, Sverdlova str., 220006, Minsk, Republic of Belarus). E-mail: narkevich@belstu.by

Farafontova Elena Valer’yevna − PhD (Physics and Mathematics), Assistant Professor, the Department of Physics. Belarusian State Technological University (13a, Sverdlova str., 220006, Minsk, Republic of Belarus). E-mail: farafontova @belstu.by

DOI: https://doi.org/ 10.52065/2520-6141-2024-284-4.

Key words: two-level statistical method, nanosystems, density fluctuation in nanoparticles.

For citation: Narkevich I. I., Farafontova E. V. Statistical research of density field fluctuations in spherical molecular nanoparticles. Proceedings of BSTU, issue 3, Physics and Mathematics. Informatics, 2024, no. 2 (284), pp. 25–30 (In Russian). DOI: 10.52065/2520-6141-2024-284-4.

Abstract

Previously, the first steps were taken to practically implement the idea of the fundamental possibility of an abbreviated description of density field fluctuations using the introduced chain of correlative functions for an ensemble of interacting elementary density fluctuations (EDF). With a certain probability, they appear and disappear randomly against the background of a homogeneous macroscopic system with given thermodynamic parameters and therefore they can be considered as quasiparticles. Their correlative functions are introduced in the same way as was done for a system of real particles (atoms or molecules) in the well-known Bogolyubov – Born – Green – Kirkwood – Yvon (BBGKY) method. As potentials of interaction of EDFs with a homogeneous medium (without taking into account fluctuations) and among themselves, this work uses the formation energies of single and paired (binary) EDFs, the calculation of which is possible within the framework of a two-level statistical method for describing the properties of inhomogeneous systems, one of the examples of which is systems with a fluctuative density field. Specific numerical calculations were performed for a simple molecular system with Lennard-Jones interparticle interaction, which is a spherical nanoparticle located in a thermostat with given thermodynamic parameters (temperature and chemical potential). That is why to statistically describe such a system, a large thermodynamic potential is used, which is a functional of the density field in the presence of an EDF in the volume of the system. As a result of averaging fluctuations of the density field at two points of a spherical nanoparticle using calculated potentials for binary EFPs, the spatial correlation function of fluctuations in a spherical nanoparticle is determined, which, of course, cannot be obtained within the framework of the known fluctuation theory for macroscopic systems.

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References

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28.05.2024