3.3. QTAIM Analyses
Quantum theory of atoms in molecule (QTAIM) analyses is the most
valuable ways to calculate intermolecular interactions and consider the
nature of interactions between CO molecule and CNT or DNTs. The electron
density (ρ ) and Laplacians of electron densities
(▼2ρ ) at the bond critical points (BCP) for all
structures are shown in Table 3. The values of▼2ρ are in the ranges of
1.84×10-2 to 3.10×10-1e/a05 for CNTs,
4.21×10-2 to 1.39×10-1e/a05 for SCNTs,
8.76×10-2 to 5.92×10-1e/a05 for NCNTs and
1.76×10-2 to 2.39×10-2e/a05 for BCNTs. In this regard, the
positive values of ∇2ρ (at critical points)
indicate that the nature of these interactions is non-covalent. Based on
the values of electron densities, the orders of▼2ρ are the same as stabilities and the values
of ▼2ρ increased through increasing the
stability of complexes.