An experimental program was designed to test the hypothesis that radical- molecule complexes, possessing either an increased reactivity or an increased selectivity, could be formed at low temperature under the influence of ionizing radiation. The nitrosation of cyclohexane and 2,3dimethylbutane with nitrosyl chloride in the presence of pi bonded solvents was investigated. The influence of metal carbonyls on the reaction between olefins and carbon monoxide was determined. A research program was initiated to study the solvent effect in radiation chemistry in terms of energy transfer. (auth)