NITROGEN MONOXIDE AS AN UNUSUAL GLASS FORMER

Using electron transmission diffraction, we studied the structure and morphology of thin N2O films of different effective thickness delta, q uench condensed at temperatures T-d from 10 to 30 K. The respective ph ase diagram of morphologic states in the coordinates (delta,T-d) was c onstructed. Unlike other cryocrystals, N2O shows an unusual ability to form (meta)stable purely amorphous or substantially amorphized crysta lline states. The shape of the ''phase line'' that separates the amorp hous and crystalline states is a cupola rather than the usual smooth s tep. The shape and size of the domain of amorphous states is controlle d by heat removal conditions. The amorphous states become absolutely u nstable at a temperature close to 40 K.