Density functional study of single-wall and double-wall platinum nanotubes

The electronic structure calculations are carried out within the density functional formalism for understanding the structure and energetics of platinum nanotubes. Various single-walled platinum nanotubes (both chiral and achiral) and double-walled platinum nanotubes (only achiral) are considered here. Our calculations reveal that among six row strand nanotubes, the relaxed Pt(6,4) is most stable while among the five row strand nanotubes, the relaxed Pt(5,3) is most stable. After complete relaxation, the atomic structures of both the Pt(6,4) and Pt(5,3) nanotubes remain tubular and chiral. However, the initial chirality is not retained in the final atomic structure. The double-walled platinum nanotubes, namely, the Pt(6,6)@(13,13), Pt(5,5)@(12,12), Pt(4,4)@(11,11), and Pt(1,1)@(7,7) are studied. The atomic structures of these double-walled nanotubes remain double walled and tubular after complete relaxation. It is interesting to note that most of our results agree with the existing experimental results.