Stability of C60 and N@C60 under thermal and optical exposure

N@C60, a nitrogen atom encapsulated in a fullerene shell, has an electron-nuclear spin system with outstanding coherence properties attractive for quantum computation. The stability of this molecule is known to be limited due to thermal escape of the nitrogen atom from the C60 cage but little is known about the stability towards optical excitation, which is one possible tool for an indirect scheme to manipulate and read out quantum information. Here, we report the results of a systematic study regarding thermal and optical effects on the stability of N@C60. The central result is that stability under intense laser irradiation can be obtained when the sample remains cooled below a certain temperature. Furthermore, the effect of molecules from the atmosphere or matrix (e.g. oxygen, toluene etc.) on N@C60 is discussed with respect to spin read-out experiments and the decomposition of N@C60. As a result, appropriate experimental conditions for optical quantum state read-out of this material are identified.