Radiolabelling Measurements of Radicals Derived from Terpenoid Volatile Organic Conpounds (VOCs) Adsorbed in Porous Carbon

Abstract

Radiolabelled free radicals were formed by the addition of muonium-a radioactive hydrogen atom with a positive muon as its nucleus-to α-pinene, β-pinene, dihydrocarvone, dihydrocarveol and dipentene, each as adsorbed in porous carbon. The radicals were identified using transverse-field muon spin rotation (TF-MuSR) and the activation parameters associated with their reorientational motion were measured using longitudinal-field muon spin relaxation (LF-MuSRx). Two distinct adsorbed fractions were detected in each sample, characterised by activation energies in the range 2-6 kJ/mol and 12-16 J/mol respectively.