FAR-INFRARED SPECTRA OF N2-AR ALLOYS

The far-infrared spectra of (N2)1-xArx solid mixtures have been studied at 18 K and p=0 for 0<x<0.25. At x=0, in addition to the phonon peaks Tu(1) and Tu(2), the combination bands recently observed at high pressure have been detected. In the alloy, the width of Tu(1) increases with x while its central frequency slowly decreases. In the phase (x=0.25) a translational mode still exists, which can be derived from the Tu(1) mode of the phase. Tu(2) is nearly insensitive to the concentration of impurities, but it disappears at the - transition. A concentration x=0.05 of Kr atoms is found to enhance the intensity of absorption in solid N2 by a factor of 5. © 1989 The American Physical Society.