Third-Order Nonlinear Optical Properties of Endohedral Fullerene (H2)2@C70 and (H2O)2@C70 Accompanied by the Prospective of Novel (HF)2@C70

Abstract

In view of the experimental observation of (H2)2@C70 and (H2O)2@C70, it has been suggested that hydrogen fluoride (HF) dimer can be completely localized within the sub-nanospace inside the fullerene C70 cage. With the aim of quantum chemical prospective of (HF)2@C70, electronic structure calculations of C60 hosting H2, HF, and H2O monomers, as well as C70 hosting H2, HF, and H2O monomers and dimers, were performed by using the density functional theory, together with the quantum theory of atoms in molecules, the natural population, and interaction energy calculation. The F–H···F bonding energy inside C70 was estimated at −13.25 kcal/mol, which is smaller than that of free dimer in the gas phase (−8.37 kcal/mol). Exploration of various featured properties suggests that (HF)2@C70 may be also regarded as a unique system composed of both inter- and intramolecular interactions like (H2)2@C70 and (H2O)2@C70. In addition, absorption spectroscopy and linear and nonlinear optical coefficients of C60 hosting H2, HF...