NO DIFFUSION AND DIMER FORMATION IN A NITROGEN MATRIX STUDIED BY FTIRSPECTROSCOPY

The formation of nitric oxide dimers in a nitrogen matrix at 24.5 and 25.2 K was monitored by Fourier transform infrared spectroscopy and th e results are interpreted by a numerical simulation. The diffusion coe fficient is fitted by D = D0 exp(-E/kT), with D0 = 90 cm2 s-1 and E = 716 cm-1. The dissociation coefficient, K(c) = 2.2 X 10(19) molecule c m-3, does not change between 24 and 32 K. A C3 rotation of a NO, N2, N 2 cluster is proposed as the most probable elementary step for diffusi on. The cis- and trans-(NO)2 band intensities are evaluated relative t o the monomer.