Encapsulation effects on the structure and stability of O3, SO2, S2O, and S3 in C60, C70, and C80 fullerenes.

Density functional theory computations were conducted for O₃@C_n, SO₂@C_n, S₂O@C_n, and S₃@C_n (n = 60, 70, and 80) to examine the confinement effects on the structure and relative stability of the open and cyclic forms of O₃, SO₂, S₂O, and S₃. Our study reveals that the energy gap between open and cyclic forms of O₃, SO₂, and S₂O is significantly reduced inside the C₆₀ cage, however, the open form remains energetically more favorable. Conversely, the relative stability of the open and cyclic forms of S₃ changes inside the cages (C₆₀, C₇₀, and C₈₀), with the cyclic form becoming more stable which is less stable in the isolated state. Unlike O₃, OSO (or OOS), and SSO, open structure of S₃ and SOS transform into cyclic inside the C₆₀ cage. The guest species effect on E_gap of host cages and charge transfer between the host cage and guest species are also discussed.