Cold fusion redux
This obituary of Martin Fleischmann appears in a similar form in the latest issue of Nature. No one, of course, wants to seem carping or churlish in an obit, and I hope this achieves some kind of balance. But I have to admit that, looking back now, I couldn’t help but be reminded of how badly Pons and Fleischmann behaved while cold fusion was at its height. In particular, the way they threatened Utah physicist Michael Salamon, who tried to replicate their experiments with their own equipment, was unforgivable. And it was pretty distasteful to see Fleischmann more recently bad-mouthing all his critics, searching for ways to belittle or dismiss Mark Wrighton, Frank Close, Nate Lewis, Gary Taubes and others. As I try to say here, it’s not getting things wrong that should count against you, but how you handle it.
Martin Fleischmann, 1927-2012
Pioneering electrochemist who claimed to have discovered cold fusion
“Whatever one’s opinion about cold fusion, it should not be allowed to dominate our view of a remarkable and outstanding scientist.” This plea appears in the University of Southampton’s obituary of Martin Fleischmann, who carried out much of the work there that made him renowned as an electrochemist. It is not clear that it will be heeded.
Fleischmann died on 3rd August at the age of 85 after illness from Parkinson’s disease, heart disease and diabetes. He made substantial contributions to his discipline, being the first person to observe surface-enhanced Raman emission (now the basis of a widely used technique) and developing the use of ultramicroelectrodes as sensitive electrochemical probes. But he is best known now for his claim in 1989 to have initiated nuclear fusion on a bench top using only the kind of equipment a school lab might possess.
The ‘cold fusion’ debacle provoked bitter disputes, court cases and controversies that reverberate today. Along with polywater and homeopathy, cold fusion is now regarded as one of the most notorious cases of what chemist Irving Langmuir called ‘pathological science’ – as he put it, “the science of things that aren’t so”.
It would be wrong to draw a veil over cold fusion as an aberration in Fleischmann’s otherwise distinguished career. For it was instead an extreme example of the style that characterized his research: a willingness to suggest bold and provocative ideas, to take risks and to make imaginative leaps that could sometimes yield a rich harvest.
Fleischmann was born in Karoly Vary (Karlsbad) in Czechoslovakia in 1927. His father was of Jewish heritage and opposed Hitler’s regime; his family fled just before the German invasion to the Netherlands and then England. Fleischmann studied chemistry at Imperial College in London and, after a PhD in electrochemistry, he moved to the University of Newcastle. In 1967 he was appointed to the Faraday Chair of Chemistry at Southampton, where he explored reactions at electrode surfaces.
In 1974, Fleischmann and his coworkers observed unusually intense Raman emission (scattered light shifted in energy by the interaction with molecular vibrational states) from organic molecules adsorbed on the surface of silver electrodes. They did not immediately recognize that the enhancement was caused by the surface, and indeed the mechanism is still not fully understood – but surface-enhanced Raman spectroscopy (SERS) has become a valuable tool for investigating surface chemistry.
Around 1980 Fleischmann and Mark Wightman independently pioneered the use of ultramicroelectrodes just a few micrometres across to study otherwise-inaccessible electrode processes – for example, at low electrolyte concentrations or with very fast rates of reaction. Such innovations gave Fleischmann international repute. In 1985, two years after his early retirement from Southampton, he was elected a Fellow of the Royal Society.
Fleischmann’s longstanding interest in hydrogen surface chemistry on palladium led to the cold fusion experiments. When hydrogen molecules adsorbed onto palladium dissociate into atoms, these atoms can diffuse into the metal lattice, making the metal a ‘sponge’ able to soak up large amounts of hydrogen. Very high pressures of hydrogen can build up – perhaps, Flesichmann wondered, sufficient to trigger nuclear fusion.
Fleischmann’s retirement in 1983 freed him to conduct self-funded experiments at the University of Utah – a location conducive to Fleischmann, a passionate skier – with his former student Stanley Pons. They electrolysed solutions of lithium deuteroxide, collecting deuterium at the palladium cathode, and claimed to measure more heat output than could be accounted for by the energy fed in – a signature, they said, of deuterium fusion within the electrode. On returning in the morning to one experiment left running overnight, they found that the apparatus had been vaporized and the fume cupboard and part of the floor destroyed. Was this a particularly violent outburst of fusion?
Not until 1989 did Fleischmann, Pons and their student Marvin Hawkins move to publish their data. They discovered they were in competition with a team at Brigham Young University in Utah, led by physicist Steven Jones, which was conducting similar studies. Initially Fleischmann and Pons accused Jones of plagiarizing their ideas, but eventually the groups agreed to coordinate their announcements with a joint submission to Nature on 24th March. Yet Fleischmann and Pons first rushed a (highly uninformative) paper into print with the Journal of Electroanalytical Chemistry, organized a press conference on 23nd March, and faxed their paper to Nature that same day without telling Jones.
The rest, as they say, is history, told for example in Frank Close’s Too Hot To Handle (1991) and Gary Taubes’ Bad Science (1993). The fusion claims shocked the world: physicists had been trying for decades, at great expense but with no success, to harness nuclear fusion for energy generation. Now it appeared that chemists had achieved it at a minuscule fraction of the expense, potentially solving the energy crisis. Jones’ paper was eventually [Nature 338, 737; 1989] published by Nature; that of Pons, Fleischmann and Hawkins was withdrawn when the authors professed to be too busy, in the wake of their astounding announcement, to address the reviewers’ comments. When Pons spoke at the spring meeting of the American Chemical Society on 12th April, the atmosphere was jubilant: it was hailed as a triumph of chemistry over physics. Physicists were more sceptical, and pointed out serious problems with Fleischmann and Pons’ claims to have detected the emission of neutrons diagnostic of deuterium fusion.
Accusations that they had manipulated the neutron data were never substantiated, but what really put paid to cold fusion was the persistent failure of other groups to reliably reproduce the purported excess heat generation and other signatures of potential fusion. More accusations, recriminations and general bad behaviour followed: coercion, intimidation, litigation (Pons’ lawyer threatened Utah physicist Michael Salamon with legal action after he published his negative attempts at replication in Nature), withholding of data (Fleischmann refused outright at one meeting of physicists to discuss crucial control experiments), and suspicions of experimental tampering (were some groups spiking their equipment with tritium, a fingerprint of fusion?). The University of Utah sought aggressively to capitalize, throwing $5m at a ‘National Cold Fusion Institute’ that closed only two years after it opened.
Once cold fusion lost its credibility, Fleischmann and Pons moved to France to continue their work with private funding, but later fell out. Now only a few lone ‘believers’ pursue the work. Fleischmann did not distinguish himself in the aftermath, belittling critical peers in interviews and hinting at paranoid conspiracy theories. But perhaps the biggest casualty of cold fusion was electrochemistry itself, suddenly made to seem a morass of charlatanism and poor technique. That was unfair: some of the most authoritative (negative) attempts to replicate the results were conducted by electrochemists.
Flesichmann’s tragedy was almost Shakespearean, not least because he was himself in many ways a sympathetic character: resourceful, energetic, immensely inventive and remembered warmly by collaborators. As Linus Pauling and Fred Hoyle also exemplified, once you’ve been proved right against the odds, it becomes harder to accept the possibility of error. “Many a time in my life I have been accused of coming up with crazy ideas,” he once said. “Fortunately, I'm able to say that, so far, the critics have had to back off.” But although a final reckoning should not let genuine achievements be overshadowed by errors, the blot that cold fusion left on Fleischmann’s reputation is hard to expunge. To make a mistake or a premature claim, even to fall prey to self-deception, is a risk any scientist runs. The true test is how one deals with it.