Calculation of the P-T phase diagram of nitrogen using a mean field model


Enginer Y., Algul G., YURTSEVEN H. H.

INTERNATIONAL JOURNAL OF MODERN PHYSICS B, vol.31, no.31, 2017 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 31 Issue: 31
  • Publication Date: 2017
  • Doi Number: 10.1142/s0217979217502459
  • Title of Journal : INTERNATIONAL JOURNAL OF MODERN PHYSICS B
  • Keywords: P-T phase diagram, Landau phenomenological model, nitrogen, X-RAY-DIFFRACTION, SOLID NITROGEN, HIGH-PRESSURE, RAMAN-SPECTROSCOPY, 2ND-ORDER TRANSITION, LATTICE-DYNAMICS, DELTA-PHASE, GPA, N-2, TEMPERATURES

Abstract

The P-T phase diagram is calculated at low and moderate pressures by obtaining the phase line equations for the transitions considered in nitrogen using the Landau phenomenological model. For some transitions, a quadratic coupling between the order parameters is taken into account in the expansion of free energies in terms of the order parameters. A quadratic function in T and P is fitted to the experimental P-T data from the literature and the fitted parameters are determined.