At first, we calculated the λ of all the oligomers using GFN2-xTB, an approximate density functional tight-binding method developed by the Grimme group , to see if it can be used as an accurate surrogate for B3LYP-computed reorganization energies. This method produces accurate geometries and is considerably faster than B3LYP calculations (Figures and). However, the λ calculated using GFN2-xTB does not correlate well with the λ calculated using B3LYP (Figure ).