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

Figure 1

Mims pulse sequence at microwave and radiofrequencies used to obtain the ENDOR spectra as a function of the stimulated electron spin echo amplitude from the frequency of RF pulse. The values of time delays (, ) and pulse lengths ( for MW and for RF) are given in the text.