The predicted eRCN spectrum in the 3.2−3.6 μm C-H stretching region as a function of X_H calculated using the structural de-composition described in Sect. 2.2.3 and the data in Table 2. The diamonds, squares and triangles indicate the aliphatic, olefinic and aromatic band positions, respectively (see Table 2). The data with error bars are for the diffuse ISM absorption along the Galactic Centre IRS6E line of sight (black) and Cyg OB2 No. 12 (grey) (taken from Pendleton & Allamandola 2002).