ICE Issue 9

42 The Israel Chemist and Chemical Engineer Issue 9 · January 2023 · Tevet 5783 History of Chemistry Articles His passing away has left a void impossible to fill. Yet I consider myself privileged and fortunate to have known him. The amount of cheerfulness, knowledge, care, concern, friendliness, and comfort that he has given each one around him, I hope will lead me ahead in my journey. The contagious energy and enthusiasm when he was around is what I would like to carry in his absence. By behaving the ‘Shimon way’, he taught me how to treat others, how to be humble yet competitive, ambitious but aware of our own limitations, and finally to respect everyone for what they are. I will be missing Shimon, yet Shimon will always be around. Elena Vinogradov When I was accepted to the PhD program at the Weizmann Institute I was elated and somewhat surprised. I was not sure what I would study, but I was quite sure it would not be NMR. In fact, during the admission interview I was asked about NMR and I told them, honestly: “I don’t knowmuch about it, I am not interested in it and I prefer not to answer any questions about it”. Despite my hutzpah, I was accepted. And then, I had to take a quantum mechanics course. And I was privileged to meet the best teacher I had ever met and one of the best people I was fortunate to encounter. Shimon’s approach to teaching stunned me. He rarely gave a straight answer. He was always asking what we thought. He was actually making sure that we understood. He was always saying that he does not know/remember or only recently understood the answer. It was always “answering a question with a question”, but taken to unbelievable levels of scientific curiosity. I was hooked on the discussion. On the opportunity to think. I thought to myself that it would be interesting to do a rotation in his lab. The rest “is history”. My first project was under the supervision of him and Professor Zeev Luz (another giant of NMR). The project failed, but the remnants of the simulation code came useful in the next steps. I was lucky to join Madhu and work on the PMLG experiment. The most challenging and rewarding part was the derivation of the bimodal Floquet theory and its application to describe the combined effects of MAS and periodic RF. We spent countless hours going over the equations, of course with me trying mostly to catch up with what Shimon had already understood. Many times Shimon would come in the morning and say something like “I was thinking about it…” which would start derivations and discussions that ensued for several days. The whiteboard would be covered with formulas, and signs of “do not erase” would be written. Floquet theory described all the experiments beautifully. Not only were we able to explain experimental observations (broadenings at specific spinning frequencies) but also to predict experimental how to adapt his explanation of a topic to the person he was talking to. At the very beginning of my masters, I was starting to write simulations of DNP, but I did not fully understand what I was doing. One day, I was simulating a small spin system, and he had me look at the energy levels as a function of the off-resonance. He had me zoom all the way in, and then asked me what I saw. He used this exercise to explain anti-crossings and state mixing. That was the day I finally understood the simulations. I kept the piece of paper, which he wrote upside down so I could read it while he was writing, and I still have it to this day. It’s a joy to look back and realize how clearly he could explain complicated topics. Part of this paper is shown in Figure 3. Sunderasan Jayanthi I was fortunate to be associated with Shimon during my graduate studies at the Indian Institute of Science (IISc) in Bangalore. Thanks are due to Madhu for introducing me to Shimon in 2004. While at the IISc, I had frequent email conversations about NMR with Shimon, and most of the time he responded within 24 hours. He had invested time and patience in answering my NMR-related queries, and those discussions were very helpful for me in my early research, and also throughout my career. Subsequently, I joined Shimon at the Weizmann Institute as a postdoctoral student in 2010–2013. I was his last postdoctoral student who worked in a solid-state NMR project. During that time, we worked closely with Asher Schmidt and Shifi Kababya, which led us to multiple train journeys to Haifa, starting early morning, utilizing the time during our journey to discuss Floquet theory and deuterium dynamics. The eighthour computational time for a Floquet Matlab simulation was addressed in one of those train journeys with a lot of equations and, in the following week, we could reduce the computational time to a few minutes. Whenever I was stuck with the underlying theory of deuterium dynamics and adsorption-desorption kinetics of small molecules in mesopores, he reassured me that “we are together in this project, we will understand it soon.” That was more than an assurance and I realized only later, when I started my career, that the knowledge I acquired when I was with him was abundant and priceless. Whenever I reached out, he continued his support by all possible means, with no hesitation and no delay, but each time with more energy, enthusiasm and joy. He helped me tremendously in every aspect of my life, be it NMR, career, or personal life. Shimon was such a wonderful person, a “spring of wisdom” as Asher says, a humble human being and a great scientist.