Electron spin resonance studies of oriented NO₂ and NF₂ in inert matrices at low temperatures

Preferentially oriented NO 2 and NF 2 in inert matrices have been studied in some detail by electron spin resonance methods at 4.2 °K. Methods are discussed which may optimize the degree of preferential orientation of the paramagnetic species in appropriate matrices. The results demonstrate that while neon is the best host matrix for orienting NO 2 , argon is to be preferred for NF 2 . The g-values and hyperfine splitting data have been accurately determined and are compared with earlier values. Motional processes are suggested to explain the spectra obtained for NF 2 in an argon matrix in the temperature range 4–30 °K.