Rotational dynamics of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msubsup><mml:mrow><mml:mi mathvariant="normal">C</mml:mi></mml:mrow><mml:mrow><mml:mn>60</mml:mn></mml:mrow><mml:mrow><mml:mn>4</mml:mn><mml:mi mathvariant="normal">−</mml:mi></mml:mrow></mml:msubsup></mml:mrow></mml:math>and electronic excitation in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Rb</mml:mi></mml:mrow><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">C</mml:mi></mml:mrow><mml:mrow><mml:mn>60</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

10% $^{13}\mathrm{C}$ enriched ${\mathrm{Rb}}_{4}$${\mathrm{C}}_{60}$ was investigated by $^{13}\mathrm{C}$ NMR. The relaxation rates ${\mathit{T}}_{1}^{\mathrm{\ensuremath{-}}1}$ and ${\mathit{T}}_{2}^{\mathrm{\ensuremath{-}}1}$ are basically determined by reorientation of the ${\mathrm{C}}_{60}^{4\mathrm{\ensuremath{-}}}$ molecules. In addition, ${\mathit{T}}_{1}^{\mathrm{\ensuremath{-}}1}$ exhibits an activated electronic contribution with activation energy 104 meV. The same activation energy is also found in Knight-shift measurements. Both compounds, ${\mathrm{Rb}}_{4}$${\mathrm{C}}_{60}$ and ${\mathrm{K}}_{4}$${\mathrm{C}}_{60}$, exhibit the same electronic excitation with the same activation energy within experimental error. We attribute this to a local excitation into a high-spin state of the Jahn-Teller distorted ${\mathrm{C}}_{60}^{4\mathrm{\ensuremath{-}}}$.