The G cluster (30 compounds) compounds exhibited similar characteristics to those in the E cluster (Figures and). It contained no aromatic functional groups, relatively long saturated hydrocarbons, and finely branched from other functional groups. An image of this superposition is shown in Figure . The primary features are the sharp peaks corresponding to CH at approximately 3000, 1500, and 700 cm -1 . Additionally, the fingerprintarea pattern is relatively simple. The difference from the E cluster is that the valley between the peaks derived from CH (CH3) and CH (CH2) at approximately 2920 and 2850 cm -1 , respectively, is shallower than that in the E-2 cluster. Furthermore, the peak derived from the bending vibration mode of C-CH3 near 1350 cm -1 is sharper than that of the E-2 cluster.