High-Field (3.4 T) ENDOR Investigation of Asphaltenes in Native Oil and Vanadyl Complexes by Asphaltene Adsorption on Alumina Surface

Figure 3

Schematic representation of a single vanadyl porphyrin molecule. The directions of the external magnetic fields “in-plane” () and “out-of-plane” () for the W-band ENDOR measurements are shown (see Figures 4 and 5).