Photochemical reactions of linear alkane radical cations in low-temperature matrices

The radical cations of linear alkanes (n-pentane, n-heptane) trapped in var ious matrices (Freon-11, Freon-113, Freon-113a, mixture of Freon-11 and Fre on-114B2, and sulfur hexafluoride) were found to undergo the following type s of photochemical reactions: (1) charge transfer to the matrix followed by neutralization, (2) isomerization and unimolecular decomposition, and (3) deprotonation. The absorption spectra of the radical cations were character ized, and the quantum yields of reactions occurring in different matrices a t 77 K were determined. It was shown that the reaction pathway and efficien cy of the photochemical processes observed for a given radical cation in di fferent matrices with similar physical and chemical characteristics could c onsiderably differ.