Many-body interactions among adsorbed atoms and molecules within carbon nanotubes and in free space

This Letter evaluates three-body triple dipole (DDD) interactions for quasi-one-dimensional phases of He, Ne, H2, Ar, Kr and Xe confined within a bundle of nanotubes. We find a significant reduction in the pair potential well depth due to the DDD effect. We carry out ab initio calculations on linear and equilateral configurations of the H2 trimer and find that overlap interactions do not greatly change the DDD interaction in the linear configuration when the spacing is greater than about 3 Å. However, the DDD interaction alone is clearly insufficient for the triangular configurations studied.