Application of coincidence Doppler broadening spectroscopy to hydrocarbons at different substance states

Coincidence Doppler broadening spectroscopy was applied to study n-hexane (C6H14), cyclohexane (C6H12) and cyclohexanone (C6H10O), at solid, as well as liquid states. The experiments were performed in parallel with traditional positron annihilation lifetime spectroscopy. Significant positron trapping by oxygen was observed in cyclohexanone; the oxygen effect is stronger in liquid state than in solid one, which can possibly be attributed to positron solvation in polar solution. Coincidence Doppler broadening results for n-hexane and cyclohexane indicate an existence of higher energetic annihilation electrons in Ps-bubble forming liquids than that in solids.