Infrared Spectra of the Frozen Oxides of Nitrogen

Abstract
Infrared studies have been made of several oxides of nitrogen trapped at liquid‐helium temperatures in matrices of argon, N2, O2, CO2, H2, and N2O. The novel techniques permitting these studies are described. NO is found as the monomer and two forms of dimer, ``cis'' and ``trans''; the cis is more stable. NO2 is found as the monomer, the known stable dimer of planar structure, and two new dimers; one of these has the ONO–NO2 structure, and the other may be the twisted Vd form of the stable dimer. N2O3 is found in its stable form ON–NO2 and in a second form whose spectrum is consistent with the structure ONONO. Observations on covalent N2O5 are also reported.