STM-D-0493Paper2012Published and peer-reviewed

Bird’s Eye View of Phonon Models for Excess Heat in the Fleischmann–Pons Experiment

Peter L. Hagelstein

Abstract and summary · read the original at the source

In one page

This short 2012 review is Peter Hagelstein’s compact statement of the problem and of his group’s answer to it. The problem first. In the Fleischmann–Pons experiment the heat is prodigious — hundreds to tens of thousands of electron-volts for every palladium atom in the cathode, far beyond anything chemistry can supply — and the helium-4 that appears tracks the energy at a ratio near 24 million electron-volts per helium atom. Yet the fast particles that a textbook nuclear reaction would throw out are not there in matching numbers. Hagelstein’s reading of a neutron-counting argument is that each helium is born with less than twenty thousand electron-volts of that 24 million. So the energy leaves by another road. His candidate is fractionation: a coherent process that takes one 24 MeV quantum and divides it into roughly four hundred million vibrational quanta of about sixty milli-electron-volts each. Ordinary models cannot do that, because their many indirect pathways cancel; add loss at the right frequency and the cancellation lifts.

Why it matters hereChapter 12 rests on the lattice being a participant in the nuclear reaction rather than a passive container, and this is the short paper that says why that has to be true if the heat is real. It also names the mechanism the rest of the programme exists to test — the fractionation of one large nuclear quantum into hundreds of millions of vibrational quanta — and the bench experiment that would show it directly.

What it claims

01The excess heat effect in the Fleischmann–Pons experiment is prodigious: referenced to the number of atoms in the cathode, the reported energy runs from hundreds to tens of thousands of electron-volts per palladium atom, with no chemical reaction available that could produce so much, and high deuterium loading is important to seeing it at all.Section 2, Absence of energetic particles
Published and peer-reviewed
02Helium-4 in the gas is correlated with the energy produced at a ratio near 24 MeV per helium atom, as found by Miles, Bush and coworkers; and because fast helium would knock deuterons into secondary fusion and produce neutrons readily even at modest energy, while hardly any neutrons are seen in cells producing excess energy, the helium must be born with less than twenty keV of that 24 MeV.Section 2, Absence of energetic particles, closing paragraph
Published and peer-reviewed
03The two-laser experiment points to where the energy goes first. Excess heat can be stimulated with a single weak diode laser but generally does not persist once the laser is off; stimulated with two weak diode lasers it responds to the difference frequency and generally does persist, with the strongest responses correlated with compressional optical phonon modes of zero group velocity — consistent with the nuclear energy being channelled into hybrid plasmon and optical phonon modes that are low-loss near 8, 15 and 21 THz.Section 3, Two-laser experiment; Section 13, Making phonons
Published and peer-reviewed
04The quantitative statement of the puzzle: converting 23.85 MeV into optical phonon modes at 15.1 THz, that is 63 meV apiece, requires the production of about 3.78 times ten to the eighth quanta. There is no precedent for such an effect, and if it exists the new mechanism of the Fleischmann–Pons effect becomes reconcilable with nuclear and condensed matter physics.Section 4, Fractionation of a large quantum
Published and peer-reviewed
05What blocks fractionation in the ordinary spin–boson model is destructive interference: indirect coupling between distant resonant states proceeds through all possible pathways and the cancellation is almost perfect. Adding loss at the transition frequency of the two-level system removes it, and the resulting lossy model fractionates a large quantum efficiently, with the coupling strength linear in the local phonon exchange matrix element, going as the square root of the oscillator excitation and roughly linearly in the number of two-level systems — so the leverage is in having very many of them working together.Sections 5 and 6, Energy exchange between two-level systems and an oscillator, and Lossy spin–boson model and coherent energy exchange; Section 7, Excitation transfer
Published and peer-reviewed
06The material picture is testable. Because the electron density in bulk palladium deuteride is too high for molecular deuterium to form, the model places the reaction at palladium monovacancies produced by inadvertent codeposition in the outer 100 to 300 nanometres of the cathode, which fits the onset of excess power above a loading near 0.80 and a temperature dependence whose activation energy, 670 meV as Storms measured, matches helium diffusion in palladium. The named next measurement is a Raman experiment detecting the relative strength of the sidebands during excess power production in a two-laser cell, which would show directly whether the nuclear energy is going into those modes.Sections 12, 13 and 14, D2 and vacancies, Making phonons, and Getting the helium out
What to watch

Read it · abstract

Abstract

Over the past several years, we have been developing models relevant to excess heat in the Fleischmann–Pons experiment. Here we review some of the key issues, and give an account of some of the progress that we have made. The excess heat effect is prodigious, and 4He seems to be correlated with the energy, but there are no energetic particles seen in amounts commensurate with the energy. This motivated us to seek models which fractionate a large energy quantum, and the lossy spin–boson model appears to do the job. Coherent energy exchange in the fractionation limit and excitation transfer are the mechanisms required which allow us to describe a new set of reactions and associated models which seem to be relevant to the experiments. The resulting models allow us to develop interpretations for numerous experimental observations.

Peter L. Hagelstein, Research Laboratory of Electronics, Massachusetts Institute of Technology. Journal of Condensed Matter Nuclear Science 6 (2012) 169–180.

(Abstract only. The complete article is free to read at https://jcmns.org/article/72169.pdf and via https://doi.org/10.70923/001c.72169 — see the rights note for why the full text is not reproduced here. The 2022 review that carries this programme forward is at /library/stm-ae64476a73.)

The way in

https://doi.org/10.70923/001c.72169Licence checked directly. The article page and the PDF at jcmns.org carry the line ‘© 2012 ISCMNS. All rights reserved.’ and no Creative Commons statement, so only the abstract is reproduced here. The complete article is free to read at the journal. The summary, the claims and the locators below were written from the full published text, J. Condensed Matter Nucl. Sci. 6 (2012) 169–180, Research Laboratory of Electronics, Massachusetts Institute of Technology. Citation note: the publisher’s article page and the running head of the PDF both give volume 6; Hagelstein’s own later review cites this paper as volume 5, so both numbers circulate — the volume printed on the article itself is 6.

How to cite it

Peter L. Hagelstein (2012) Bird’s Eye View of Phonon Models for Excess Heat in the Fleischmann–Pons Experiment. doi:10.70923/001c.72169

Where it sits in the curriculum

Lattice confinement fusion