  Applications of negatively charged nitrogen-vacancy center in diamond exploit
the center's unique optical and spin properties, which at ambient temperature,
are predominately governed by electron-phonon interactions. Here, we
investigate these interactions at ambient and elevated temperatures by
observing the motional narrowing of the center's excited state spin resonances.
We determine that the center's Jahn-Teller dynamics are much slower than
currently believed and identify the vital role of symmetric phonon modes. Our
results have pronounced implications for center's diverse applications
(including quantum technology) and for understanding its fundamental
properties.
