Satellite phenomena in the high energy photoelectron spectra of tetramethyl-p-phenylenediamine (TMPD), tetracyanoquinodimethane (TCNQ), and their derivatives. Experimental and theoretical study

The high energy photoelectron spectra of tetramethyl-p-phenylenediamine (TMPD) and its singly and doubly ionized derivatives are presented. The singly charged species (Wurster's Blue) exhibits a pronounced satellite on the high binding energy side of the N1s peak. This satellite, together with the satellites reported previously in the N1s spectra of tetracyanoquinodimethane (TCNQ) and its radical anion salts are attributed to “shake-up” in which an electron in the highest filled molecular orbital is promoted to the first virtual orbital, accompanying core ionization. The assignments are based on modified sudden approximation calculations. The nature of the electronic interactions in these compounds is discussed in the light of the ESCA experiments.