Lee-Yang and Fisher zeros are crucial for the study of phase transitions in the grand canonical and the canonical ensembles, respectively. However, these powerful methods do not cover the isothermal-isobaric ensemble (NPT ensemble), which reflects the conditions of many experiments. In this work we present a theory of the phase transitions in terms of the zeros of the NPT-ensemble partition functions in the complex plane. The proposed theory provides an approach to calculate all the partition function zeros in the NPT ensemble, which form certain curves in the thermodynamic limit. To verify the theory we consider Tonks gas and van der Waals fluid in the NPT ensemble. In the case of Tonks gas, similarly to the Lee-Yang circle theorem, we obtain an exact equation for the zero limit curve. We also derive an approximated limit curve equation for van der Waals fluid in terms of the Szegö curve. This curve fits numerically calculated zeros and correctly describes how the phenomenon of phase transition depends on the temperature.
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http://dx.doi.org/10.1103/PhysRevE.100.052118 | DOI Listing |
J Mol Model
January 2025
Shanxi Jiangyang Chemical Limited Company, Taiyuan, 030041, Shanxi, China.
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View Article and Find Full Text PDFJ Chem Theory Comput
January 2025
Chemical and Materials Physics Graduate Program, Departments of Molecular Biology and Biochemistry, Chemical and Biomolecular Engineering, Materials Science and Engineering, and Biomedical Engineering, University of California, Irvine, Irvine, California 92697, United States.
Molecular dynamics (MD) simulations are essential for understanding molecular phenomena at the atomic level, with their accuracy largely dependent on both the employed force field and sampling. Polarizable force fields, which incorporate atomic polarization effects, represent a significant advancement in simulation technology. The polarizable Gaussian multipole (pGM) model has been noted for its accurate reproduction of ab initio electrostatic interactions.
View Article and Find Full Text PDFCarbohydr Res
March 2025
Quantitative Biology Lab, Department of Integrative Biology, School of Bio Sciences and Technology, Vellore Institute of Technology (VIT Deemed to Be University), Vellore, Tamil Nadu, India. Electronic address:
Pectate lyases, known for their alkaliphilic nature, are ideal for industrial applications that require specific pH conditions, particularly in industries such as textiles and pulp extraction. These enzymes, primarily from the polysaccharide lyase family 1 (PL1) of different microbial sources, play a vital role in polysaccharide degradation. Given the potent pectinolytic activity of Bacillus pectate lyases, targeting these enzymes is crucial for identifying the most effective candidates.
View Article and Find Full Text PDFJ Chem Phys
December 2024
Institut für Thermodynamik, Helmut-Schmidt-Universität/Universität der Bundeswehr Hamburg, Holstenhofweg 85, 22043 Hamburg, Germany.
We apply the methodology of Lustig, with which rigorous expressions for all thermodynamic properties can be derived in any statistical ensemble, to derive expressions for the calculation of thermodynamic properties in the path integral formulation of the quantum-mechanical isobaric-isothermal (NpT) ensemble. With the derived expressions, thermodynamic properties such as the density, speed of sound, or Joule-Thomson coefficient can be calculated in path integral Monte Carlo simulations, fully incorporating quantum effects without uncontrolled approximations within the well-known isomorphism between the quantum-mechanical partition function and a classical system of ring polymers. The derived expressions are verified by simulations of supercritical helium above the vapor-liquid critical point at selected state points using recent highly accurate ab initio potentials for pairwise and nonadditive three-body interactions.
View Article and Find Full Text PDFJ Mol Model
December 2024
State Key Laboratory of NBC Protection for Civilian, Beijing, 102205, China.
Context: Ammonium dinitramide (ADN) is highly hygroscopic, which poses significant challenges in its practical applications. Consequently, mitigating this hygroscopic nature has been a primary focus in the research and development of ADN. This study investigated the properties of the ADN/3-amino-4-nitrofurazan (ANF) cocrystal using density functional theory, molecular dynamics, and Monte Carlo methods.
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