Electron spin resonance spectrum of HCN− in alkali halide matrices

The electron spin resonance spectrum of a radical formed by γ-irradiation or ultra-violet photolysis of alkali halides doped with cyanide shows a very large hyperfine coupling to one proton (A iso H=137 gauss) and one carbon atom (A iso C=74 gauss). In addition a single nitrogen atom gives a triplet having a A iso N=6·5 gauss. The radical is identified as HCN- and its electronic structure is discussed. A second radical also contaming a single strongly coupled proton has been detected and is briefly discussed.