Published: 21.09.09

ETH Zurich's head of research resigns

At ETH Zurich, there are suspicions that scientific data may have been falsified in two publications and a doctoral thesis in 1999 and 2000. At the request of the then group leader Peter Chen, now Vice President Research and Corporate Relations, the Executive Board appointed a panel of experts. It concluded that data had indeed been falsified. However, it is not known for absolute certain who was responsible for the falsifications. Nevertheless, out of respect for ETH Zurich and the function as head of research, Peter Chen has acknowledged his responsibility and decided to step down as Vice President at the end of September 2009.


The research projects affected hail from the field of basic research in chemistry at ETH Zurich and were published in 2000 by members of the team then headed by Peter Chen. He has been Full Professor of Physical-Organic Chemistry since 1994 and Vice-President Research and Corporate Relations since 2007. More specifically, the matter concerns results relating to the spectroscopic structural clarification of hydrocarbon radicals: short-lived chemical compounds that are formed during combustion processes, for instance.

Intensive search for discrepancies

Special techniques are needed to reproduce such molecules spectroscopically. The experiments were conducted with the so-called “zero-kinetic-energy photoelectron spectroscopy” method, a high-resolution version of photoelectron spectroscopy. The method can be used, amongst other things, to analyze highly reactive or instable compounds. The measurements include electrons that break away from the molecule under examination after it has absorbed light. The spectra determined as a result can then be used to analyze the geometric structure and dynamics of the compounds.

After the projects were published, however, other research groups working in the same field obtained significantly different results. Subsequently, Peter Chen’s group set about seeking an explanation for the discrepancies in conjunction with a former post-doctoral researcher’s group. The discrepancies initially involved the ionization energy of alkyl radicals. Ionization energy means any energy needed to separate the least stable electron from an atom in its basic state.

Commission confirms falsification of data

Not only was the attempt to reproduce the values measured unsuccessful, but also the search for other explanations for the inconsistencies. Peter Chen began to suspect foul play. He called upon the Executive Board of ETH Zurich to appoint a scientific board of inquiry to clarify the irregularities at the beginning of January 2009. At the same time, he and his co-authors withdrew an initial publication.

In keeping with its legal obligation to pursue any concrete suspicion of misconduct in research, the Executive Board entrusted five internationally renowned professors (three external ones and two from ETH Zurich) with the task. The commission scrutinized the studies in question, repeated the processes used at the time where possible and interviewed the three authors involved in the experiments: the doctoral and post-doctoral students at the time and Peter Chen.

The commission concluded that some of the data the publications and the doctoral thesis were based on had been falsified. For instance, certain diagrams involving representations of the measured spectra often contained identical patterns from static, i.e. technically unavoidable signals without any discernable information content. The fact that some of the noise patterns recur in an identical fashion is virtually impossible, which suggests they were added to the diagrams afterwards. Moreover, re-measurements revealed that some of the lines apparently measured within the spectra actually did not exist, i.e. did not show up in the repetition of the experiments. What is more, the relevant lab books and most of the raw data for the experiments are missing, which is very odd. This means that how the questionable data was obtained can no longer be reproduced accurately. At any rate, the commission decided that the second publication and the doctoral thesis would also have to be withdrawn.

Publications withdrawn – question of guilt not resolved beyond reasonable doubt

All of the people involved in the experiments categorically deny having carried out the falsifications; however, they all agree that the data was falsified. Consequently, the second publication with the dubious data was withdrawn. The researchers are thus fulfilling their individual responsibility for the accuracy of data. Furthermore, the author of the doctoral thesis initially withdrew it of his own accord, but retracted the withdrawal later. In this context, the Executive Board of ETH Zurich has postponed the planned publication of the commission’s report for the time being for legal reasons.

The Executive Board conducted further talks and viewed documents to form its own opinion. “The commission resolved the matter objectively and I am much obliged to them in the name of ETH Zurich”, says ETH President Ralph Eichler. “Unfortunately, there is now no legal way of finding out for sure who was responsible for the falsifications”, he continues.

Vice President Research assumes responsibility

For Peter Chen himself, it is clear: as the head of the research group at the time, he acknowledges his responsibility. As the current vice-president responsible for quality assurance in research, however, he feels especially affected and considers his ability to act compromised. With regard to ETH Zurich’s excellent reputation, he has decided to step down as Vice President Research and Corporate Relations at the end of September 2009.

The Executive Board deeply regrets this development. “Peter Chen is an impressive researcher and a highly valued member of our board in every respect”, stresses Ralph Eichler. “We very much regret to lose such an accomplished leader, but we are happy that he’ll remain in our midst as a model colleague, outstanding scientist and professor.”

The research system is built on adherence of the facts, honesty and trust, and ETH Zurich does everything in its power to safeguard these values as an absolute prerequisite for research. “Scientific misconduct jeopardizes the very core of research and must carry consequences”, says Ralph Eichler. “This has been the case here and the matter also shows that the established control mechanisms for research really do work.”