Stationary stochastic adparticle flip-flop as a precursor to surface diffusion

Abstract

Prediffusion single adparticle motion between two (flip‐flop) or more states of a double or multiple well potential is reported for flavanthrene molecules. The field dependence of the mean residence times is measured by a field emission probe‐hole technique and is discussed in terms of changes of the effective adparticle polarizability. Some preliminary FIM flip‐flop observations are discussed. Consequences of prediffusion flip‐flop for adsorbate field emission flicker noise and evidence for a Cremer‐Constable relation of adsorbate flip‐flop activation energies and pre‐exponentials are shown.

Electronic energy levels of porphyrins are influenced by the local chemical environment

“…[29][30][31][32] The existence of bistable switchable states is the rst step towards use of porphyrins in applications of molecular memory storage or binary devices. 33 Pyrrolic macrocycles have been shown to exhibit bistable switching behavior on surfaces including induced conformational switching, [34][35][36] orientational ip-opping, [37][38][39][40][41] and tautomerization. [42][43][44][45][46] Examples include subphthalocyanine arrays that adsorb with a shuttlecock shape and exhibit scanning tunneling microscopy (STM) induced reversible orientational switching on Cu(100), 37 and current from the STM tip that has been used to induce hydrogen tautomerization in naphthalocyanine on an NaCl bilayer on Cu(111).…”