STUDY OF MATRIX-ISOLATION OF NITROGEN-ATOMS IN SOLID N-2

The process of matrix isolation of nitrogen atoms in solid Nz is studi ed by the method of condensation from the gaseous phase. In order to v ary the flow rates of nitrogen atoms and molecules at the sample surfa ce over a wide range, N-2-He mixtures of various compositions have bee n passed through the gas discharge zone. It is found that the EPR line width for N atoms in N-2 increases upon a decrease in the nitrogen fl ow rate from the discharge zone to a cold substrate. It is shown that this increase is due to an increase in the concentration of atomic nit rogen in the matrix leading to an enhancement of the dipole-dipole int eraction between atoms. It is established that a decrease in the inten sity of recombination of atoms in the course of diffusion at the sampl e surface due to a decrease in the surface density of these atoms play s a decisive role in the growth of the concentration of matrix-isolate d atoms in the experiments. It is found that for a constant flow rate of atoms from the discharge, their concentration in the matrix increas es and attains saturation upon an increase in the discharge intensity. The dependence of concentration on the discharge intensity is attribu ted to a change in the degree of dissociation of molecular nitrogen in the discharge. (C) 1998 American Institute of Physics.