Dear all, In a recent private discussion about impurities in an electrolytic cell, e.g. Si from the cell's glass walls (chemically etched by LiOD), or Pt from the anode (ever so slowly etched, but nonetheless etched by anodic dissolution), an esteemed colleague judiciously pointed out that only a few micrograms of Si or Pt per cm^2 would be enough for the cathode's bulk metal surface to be entirely covered.
It just occurred to me that the hypothetical DIESECF mechanism might not necessarily occur exclusively at the surface of the highly H/D permeable base metal itself (e.g. Pd) where it is exposed, but also (or alternatively) at the surface of the impurity layer where it constitutes the outermost cathode surface! Indeed, where the base metal is covered, the surface of the impurity layer is where the (screening) excess surface electrons dwell, and the impurity layer is initially so thin that it must be very hydrogen-permeable (all materials being permeable to H/D to some extent, and permeation rate being inversely proportional to thickness), so that it cannot "clog" the (e.g. Pd) bulk metal, or at least not until it becomes thick enough. In this I-DIESECF (Impurity-based DIESECF) variant, the role of the *still indispensable* highly permeable metal base (e.g. Pd) would then be to feed the impurity layer with the required H/D desorbing flow. Comments/objections welcome as always. Michel ------------------------------------------------------------------------ (*) Reminder: DIESECF = Desorbing [H+/D+] vs Incident [H+/D+] Excess Surface Electron Catalyzed Fusion: a nucleus exiting the metal lattice (desorbing H+/D+) fuses inadvertently with one impinging on the lattice (incident H+/D+), while chasing the same surface electron(s) screening their mutual repulsion. DIESECF FAQ ------------ Why "Excess Surface Electron Catalyzed"? ------------------------------------- In a metal, excess electrons, obviously more effective at coulomb repulsion screening than electrons in a net neutral place, cannot (except fugitively) be found anywhere but on the surface, e.g. when such surface is the cathodic surface of a gas discharge cell, or that of a water electrolysis cell. In the latter case, this thin excess electron layer is particularly rich due to the water molecule-thin electrochemical double layer, a.k.a. Helmholtz double layer, the astronomically high charge storage phenomenon exploited in supercapacitors: http://http://en.wikipedia.org/wiki/Supercapacitor Why "Desorbing vs Incident"? --------------------------- Hydrogen nuclei (e.g. deuterons) on the same side of the electron screen (either both desorbing, or both incident from the electrolyte or the gas medium) repel each other, so they are necessarily far away from each other, typically 1 Angstrom or more. Whereas deuterons coming from opposite sides, "hidden" from each other by the thin excess surface electron screen (~0.02 Angstrom thickness estimated from charge displacement considerations), have a sizeable probability to get close enough to fuse. How can one maximize the fusion rate if the hypothesis is correct? ------------------------------------------------------------------ The DIESECF mechanism is analogous to car collisions at an unsignaled street intersection (analogous of the metal surface pore), where the analogous of the excess electron screen would be a local streak of fog resulting in drivers on a collision course only seeing each other at the last moment, making their late braking ineffective at preventing the collision. At such a street crossing it is well known that the collision rate increases with the _product_ of the respective traffics (for high collision rate both traffics must be as high as possible, zero traffic in one of the streets implies zero collision whatever the traffic in the other street obviously) Likewise, for a given cathode area (a given number of "intersections"), conditions maximizing the _product_ of simultaneous desorbing and incident flows should be promoted at the cathode surface... which may be the cathode's base metal surface... or the impurity layer surface as discussed above! It will be interesting to test which works best, and if the latter, which impurities work best! Any help to estimate the fusion rate depending on the surface material would be welcome BTW.
