MIXTURES OF (N-2)(1-X)(O-2)(X) AT HIGH-PRESSURES AND LOW-TEMPERATURES

We performed Raman measurements at 18 K and pressures up to 25 GPa in order to construct a tentative phase diagram of the (N-2)(1-x):(O-2)(x )-system at low temperatures. We varied the composition of the mixed s ystem over the whole concentration range. Here we focused on the syste ms with high nitrogen concentration and pressures above 2 GPa. It is k nown that at room temperature oxygen is highly solvable in the delta-p hase of N-2. The experimental results show that oxygen suppresses the disorder-order transition delta --> epsilon-N-2.