CALCULATION OF THE PRESSURE-INDUCED INSULATOR-METAL TRANSITION OF NITROGEN

Previous theoretical predictions of metallization below 1000 kbar are in apparent disagreement with the experimental fact that nitrogen is observed to remain a molecular solid up to 1300 kbar. The 0 K transition pressure from molecular to monatomic nitrogen is calculated using simple models and a well tested pair potential, The computed coexistence pressure is found to be 1940 kbar with a volume change of 20 Bohr(3)/atom. Although there is some uncertainty (about 18%) in the calculated pressure, it is clear that non-molecular nitrogen could be studied at experimentally accessible pressures.