NONMOLECULAR NITROGEN has been observed by scientists at the Carnegie Institution of Washington. Because of the triple bond involved, diatomic nitrogen is one of the most strongly bonded simple molecules in nature. Atomic nitrogen has not been seen at ambient conditions and was thought to exist only under conditions of very high pressure, such as those one might find at the core of Jupiter.

The Carnegie group (Alex Goncharov, Eugene Gregoryanz, Russell Hemley, David Mao and Zhenxian Liu, 202-686-2410), begins with gaseous N2 and then squeezes until, at pressures above 150 GPa, optical hints (an overall opaqueness--see figure at Physics News Graphics --and the disappearance of radiation corresponding to the rotational and vibrational states, which one associates with molecules) indicate that the N2 molecules have dissociated into atomic N. In this state, the nitrogen appears to be semiconducting, and might yet become metallic at still higher pressures, above 275 GPa, which is being explored presently by the Carnegie researchers. (Goncharov et al., Physical Review Letters, 7 August; Select Articles.)