Metallization and molecular dissociation of dense fluid nitrogen

• Published in: Nature communications Vol. 9; no. 1; pp. 2624 - 6
• Main Authors: Jiang, Shuqing, Holtgrewe, Nicholas, Lobanov, Sergey S., Su, Fuhai, Mahmood, Mohammad F., McWilliams, R. Stewart, Goncharov, Alexander F.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 06.07.2018; Nature Publishing Group; Nature Portfolio
• Subjects: 140/125; 140/133; 639/301/119/2795; 639/638/440/94; 639/766/119/995; Chemical bonds; Humanities and Social Sciences; Laser beam heating; Metallizing; Molecular chains; multidisciplinary; Nitrogen; Optical properties; Organic chemistry; Polymerization; Polymers; Polymorphism; Science; Science (multidisciplinary); Spectroscopy
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-018-05011-z

Diatomic nitrogen is an archetypal molecular system known for its exceptional stability and complex behavior at high pressures and temperatures, including rich solid polymorphism, formation of energetic states, and an insulator-to-metal transformation coupled to a change in chemical bonding. However, the thermobaric conditions of the fluid molecular–polymer phase boundary and associated metallization have not been experimentally established. Here, by applying dynamic laser heating of compressed nitrogen and using fast optical spectroscopy to study electronic properties, we observe a transformation from insulating (molecular) to conducting dense fluid nitrogen at temperatures that decrease with pressure and establish that metallization, and presumably fluid polymerization, occurs above 125 GPa at 2500 K. Our observations create a better understanding of the interplay between molecular dissociation, melting, and metallization revealing features that are common in simple molecular systems. Nitrogen is a model system still presenting unknown behaviors at the pressures and temperatures typical of deep planets’ interiors. Here the authors explore, by pulsed laser heating in a diamond anvil cell and optical measurements, the metallization and non-molecular states of nitrogen in a previously unexplored domain above 1 Mbar and at 2000-7000K.