Impact of confining hydrogen molecule inside fullerenes: A glance through DFT study.

Context: In this work, we have studied different properties of a series of fullerenes, from C to C by confining hydrogen molecule inside their cavity. The compression of the hydrogen molecule upon encapsulation is evidenced by its altered bond length, while a slight expansion of the fullerene cages due to H confinement is also noted. The chemical reactivity parameters of both the empty and H confined fullerenes are computed, alongside an examination of the energy components through energy decomposition analysis. Analysis of the absorption spectra indicated that both H encapsulated and empty fullerenes exhibited absorption in the UV region. Nevertheless, the inclusion of H within the fullerene cages appeared to have minimal influence on the reactivity parameters and absorption spectra, as evidenced by the comparison between the sets of empty and H-confined fullerenes.

Methods: The computational work including the geometry optimization, followed by the frequency analysis and other parameters has been achieved using Gaussian09 software. For doing these calculations, B3LYP and CAM-B3LYP functionals along with 6-311 + G(d,p) basis set is used. In addition, MULTIWFN software has been considered for studying bonding analysis and energy decomposition analysis for the systems.