Polarization Symmetry Breaking in Nitrogen under High Pressure

TL;DR

This paper investigates how polarization symmetry breaking influences nitrogen's phase transitions under high pressure, revealing a transition pathway from molecular fluid to polymeric phases through symmetry considerations.

Contribution

It introduces an order parameter for polarization symmetry breaking in nitrogen and describes its pressure dependence with a power law, highlighting the role of symmetry in phase transitions.

Findings

Order parameter describes dissociation transition

Power law P=kq2 fits experimental data

Symmetry breaking facilitates phase change

Abstract

An order parameter with broken polarization symmetry is proposed for the pressure-induced molecular dissociation transitions in nitrogen. The experimental dissociative transition pressure dependence of the calculated order parameter is well described by a power law of the form P=kq2. Our results unveil the important role of symmetry breaking in nitrogen under high pressure and further demonstrate a path from dense molecular fluid to fully polymeric phases by breaking local polarization reversal symmetry.