Linear and nonlinear optical properties of M@C59X (M = Li, Na and X = B, N) cage

By applying the density functional theory (DFT) combined with sum-over-orbital (SOO) approach, the static and frequency dependent nonlinear optical (NLO) properties of the C60 and M@C59X cages have been studied. The NLO properties of the C60 cage have been investigated by considering effects of substitution of one B or N atom at one of C sites and Li or Na atoms encapsulation in the C60 cage (SED). The numerical results show that the polarizabilities and second hyperpolarizabilities values of the C60 cage can greatly vary with respect to SED type. As, highest peak value of second hyperpolarizabilities for Na@C59N is about 34, 1.8 and 1.1 times larger than that of the C60, Li@C59X and Na@C59B cages, respectively. These results can be important to experimentalists for designing new NLO materials with large NLO responses.