Environmental effects on electron spin relaxation inN@C60

Abstract

We examine environmental effects of surrounding nuclear spins on the electron spin relaxation of the $\mathrm{N}@{\mathrm{C}}_{60}$ molecule (which consists of a nitrogen atom at the center of a fullerene cage). Using dilute solutions of $\mathrm{N}@{\mathrm{C}}_{60}$ in regular and deuterated toluene, we observe and model the effect of translational diffusion of nuclear spins of the solvent molecules on the $\mathrm{N}@{\mathrm{C}}_{60}$ electron spin relaxation times. We also study spin relaxation in frozen solutions of $\mathrm{N}@{\mathrm{C}}_{60}$ in $\mathrm{C}{\mathrm{S}}_{2}$, to which small quantities of a glassing agent, ${\mathrm{S}}_{2}{\mathrm{Cl}}_{2}$, are added. At low temperatures, spin relaxation is caused by spectral diffusion of surrounding nuclear $^{35,37}\mathrm{Cl}$ spins in the ${\mathrm{S}}_{2}{\mathrm{Cl}}_{2}$, but, nevertheless, at $20\phantom{\rule{0.3em}{0ex}}\mathrm{K}$, ${T}_{2}$ as long as $0.23\phantom{\rule{0.3em}{0ex}}\mathrm{ms}$ is observed.