Special Issue Preface pubs.acs.org/JPCA
Tribute to Jean-Michel Mestdagh new domain of investigation. Returning to Saclay, new molecular beam machines were constructed in the group of J. Berlande, and Jean-Michel was very active in the think tank of reaction dynamics in France initiated by J. P. Lehman and Raymond Vetter, the GdR “ Dynamique réactionnelle”. Meanwhile he established many successful international collaborations with Y. Lee, A. Suits, J. Frey, and others. Then, combined with the interest of high-intensity laser physicists toward femtosecond lasers at the CEA, Jean-Michel and Jean-Paul Visticot saw a fantastic opportunity to have a facility fully dedicated to femtochemistry, the time-dependent view of reaction dynamics initiated in the 80s by A. H. Zewail, R. Hochstrasser, and others. This has led to the European facility “SLIC” (Saclay Laser-matter Interaction Center) that has hosted many fruitful experiments. Another innovative approach of reaction dynamics was developed together with Jean-Paul Visticot by Jean-Michel, in which large argon clusters could be used as nanoreactors to support chemical reactions at their surface. Compared with crossed beam experiments, clusters increase by several orders of magnitude the reaction cross-section as determined by their capture size. Thus, low-temperature chemiluminescence reactions were investigated on the epitomic electronically excited Ba+N2O system. This was the first on a series of new and successful experiments. When Jean-Michel took the lead of the reaction dynamics group in Saclay, he decided to leave the experimental side of his research only to advising. Being attracted by theoretical concepts and the need to model the experimental results, he naturally became a quantum chemist. Besides, this situation is the best for theoretical modeling since as an experimental actor he knew all the details of the experiments and their pitfalls and strengths. This situation provides a more intimate comprehension of phenomena. In some ways, as a piano player, JeanMichel anticipated the “keyboard-chemistry” age: Why perform unnecessary experiments if you can model them?! He thinks you cannot get away without both experiment and theory. Lately, following the redeployment of the research in chemical physics (and physical sciences) of the Orsay and Saclay campuses, he has been intimately involved in the organization of the future departments of the now “Paris-Saclay University”. He has struggled to keep effective links between the chemical and the physical departments. To anyone who has met Jean-Michel, his prodigious interest in understanding the scientific world is obvious, whatever the topic. He is keen at deciphering any problem, experimental, theoretical, or mathematical. It is always enriching to discuss with him confusing problems. Besides, often he will bring out the solution, as if you would have come to it by yourself. This is the sign of his unselfishness and open generosity. Scientists are actors of their research and have their egos. One must remember that the organization of research that
A
fter being tentatively seduced by astrophysics, Jean-Michel Mestdagh entered in the mid-1970s the realm of atomic collisions in the golden era of crossed beam studies, studying inelastic atomic collisions. Maybe his research direction was influenced by his passion, mountaineering. Indeed, Jean-Michel Mestdagh likes the summits, in many domains. He loves topological problems like climbing up to saddle points and in general potential energy surfaces. His scientific interests have naturally turned toward reaction dynamics. Reaction dynamics was an entirely new way to envision chemistry as Dudley Herschbach, John Polanyi, R. N. Zare, Yuan T. Lee, and many others imagined, through the examination of the forces that drive reactants to products over potential energy surfaces. It was certainly beyond the thermodynamic age, and the interaction between reactants could be directly probed through the recoil of the reaction fragments. The typical reactive systems were metal atoms with halogen molecules, and one could visualize the hooking of the metal by an electron jump to the halogen. This approach was generalized through the 60s by the success of the studies in crossed beam collisions describing the ballistics of the single reactive encounter. When Jean-Michel undertook postdoctoral research with Y. T. Lee at Berkeley in 1983−1984, the equivalent dynamics of reactions involving excited state species had just begun with the use of lasers; this was the opening of a © 2015 American Chemical Society
Special Issue: Jean-Michel Mestdagh Festschrift Published: June 11, 2015 5901
DOI: 10.1021/acs.jpca.5b03158 J. Phys. Chem. A 2015, 119, 5901−5902
Special Issue Preface
The Journal of Physical Chemistry A prevailed in the years 1970−2000 in France lessened the exaltation of the personalities and developed an exciting atmosphere for research through a collective effort of senior scientists. This has driven the team formed by Jean-Michel, Jean-Paul Visticot, Marc-André Gaveau and others, initiating, enlightening students and younger scientists. Most importantly, Jean-Michel has teaching talents. One day he was called for a lecture in a graduate course he had forgotten to give. He came to deliver it, off hand with brio, as if fully prepared to do it. Jean-Michel has been the mentor of many students. Former students are all grateful to him, not only for his teaching qualities and scientific advice but also for his great human qualities. It is with great patience and clarity that he enlightens the various problems that his students have faced. He has guided them in solving these scientific issues and has always been able to give students the feeling that they had succeeded in solving the problem by themselves. As a young grandfather, he will continue his teaching work, and no one doubts that he will endeavor to apply his talents.
Marc Briant Lionel Poisson Niloufar Shafizadeh Benoît Soep
5902
DOI: 10.1021/acs.jpca.5b03158 J. Phys. Chem. A 2015, 119, 5901−5902
