Molecular rotation and isomerisation in hydrogen isocyanide

Abstract

Molecular rotation appears to accelerate the randomisation of energy in the HNC molecule, but in the limit of very high rotational energy, it reduces the overall rate of isomerisation. Since the rotational motion is highly regular, but the vibrational motion is only partly so, various qualitative indicators of chaotic behaviour give conflicting diagnoses.Parallel calculations on the isomerisation of isocyanogen (CN—CN) to cyanogen (NC—CN) reveal that isocyanogen behaves more like the small molecule HNC than the large molecule CH3NC.