The effect of strong electric fields and local charging on surface phenomena and in more homogeneous chemical environments (e.g. enzymes) are gradually recognized to be important in driving and directing chemical and photochemical processes.
In this lecture I will discuss three model systems where static and transient electric fields of more than 107 V/m are formed, all under well-defined ultra-high vacuum (UHV) conditions. The first is a model plate capacitor, obtained by charging positively (ions) or negatively (low energy electrons) a variable thickness layer of amorphous solid water (ASW) adsorbed on a metal substrate. We demonstrate that such static fields may affect the outcome of a UV-photon and low energy electrons reactivity of probe molecules trapped within the thin ASW film1.
When pulsed lasers are exciting sharp edges of silicon or objects at the vicinity of plasmonic (e.g. Ag) nano-structures, one expects strong transient fields to be generated. Extremely large desorption cross sections of Xe atoms and CO molecules at sharp edges of porous silicon substrate2 and the dominant role of hot electrons generated in nanostructures of silver (and not their local plasmonic fields)3 will be demonstrated and discussed.
1. Y. Horowitz and M. Asscher, J. Chem. Phys., 139, 154707 (2013).
2. G. Toker et. al., Phys. Rev. Lett., 107, 167402-16406 (2011).
3. G. Toker et. al., Nano Letters, 15(2), 936-42 (2015).