Coupled Translation–Rotation Dynamics of H ₂ and H ₂ O Inside C ₆₀ : Rigorous Quantum Treatment

Experimental determination of the interaction potential between a helium atom and the interior surface of a C60 fullerene molecule

“…22,32,34,41,43 The quantum structure has been studied in detail using models of the confining potential, sometimes combined with cage-induced modifications of the rotational and vibrational characteristics of the guest molecule. 32,33,35,36,[43][44][45][46][47][48][49][50][51][52][53][54][55][56] There are two main ways to describe the interaction potential between the encapsulated species and the cage. One approach describes the interaction potential as a sum over many two-body Lennard-Jones (LJ) functions involving each endohedral atom and all 60 carbon atoms of the cage, [44][45][46]49,50,52,53,55,56 sometimes introducing "additional sites" on the endohedral species as well.…”

“…32,33,35,36,[43][44][45][46][47][48][49][50][51][52][53][54][55][56] There are two main ways to describe the interaction potential between the encapsulated species and the cage. One approach describes the interaction potential as a sum over many two-body Lennard-Jones (LJ) functions involving each endohedral atom and all 60 carbon atoms of the cage, [44][45][46]49,50,52,53,55,56 sometimes introducing "additional sites" on the endohedral species as well. 46,52,53 One disadvantage of this approach is that the summed potential has an undesirable dependence on the precise radius of the encapsulating fullerene cage.…”

“…One approach describes the interaction potential as a sum over many two-body Lennard-Jones (LJ) functions involving each endohedral atom and all 60 carbon atoms of the cage, [44][45][46]49,50,52,53,55,56 sometimes introducing "additional sites" on the endohedral species as well. 46,52,53 One disadvantage of this approach is that the summed potential has an undesirable dependence on the precise radius of the encapsulating fullerene cage. An alternative approach, which we call "model-free," describes the interaction potential as a sum of orthogonal spatial functions.…”

Noncovalently bound molecular complexes beyond diatom–diatom systems: full-dimensional, fully coupled quantum calculations of rovibrational states

“…The spectroscopy and dynamics of guest molecules in H 2 O@C 60 and other LMEFs are dominated by nuclear quantum effects (NQEs), 59,110,118 especially for the low temperatures (typically ranging from 1.5 K to about 30 K) at which the spectroscopic measurements are usually carried out. The NQEs arise from a combination of quantization of the translational c.m.…”

“…These calculations 58 also showed that the TR level structure of H 2 O@C 60 exhibits all of the key qualitative features identified previously for H 2 @C 60 . 56,59,118,127…”