Encounters with John Van Vleck: Elevating the Self-Esteem of an Experimentalist

As a Harvard freshman in 1960, John H. Van Vleck was assigned to guide me through physics course selections. As a Harvard first year graduate student in 1964, I took his course on Group Theory. He was an esteemed theoretician, and I was an experimentalist. Nevertheless, I liked him, and he both educated me and gave me good advice. Later, I learned that Van Vleck was responsible for bringing Nicolaas Bloembergen, my Ph. D. advisor, back to Harvard from Holland, with a faculty appointment in the Division of Engineering and Applied Physics. (Bloembergen had done his Ph.D. thesis with Ed Purcell, making NMR into a science, and Purcell was one of the best teachers I encountered in 9 years at Harvard.) Stepping forward in time to May, 1969, just after defending my doctoral thesis, I ran into Van Vleck in the hallway. I told him I had earned my Ph.D., and he asked me what I had done for my thesis. Feeling defensive while talking to a great theoretician, I started out cautiously to say that I had built a carbon dioxide laser. He immediately started praising me as the best of the breed, someone who could build things and actually make them work. The praise continued, he told some stories (which I will share), and I left the building on ``Cloud 9.'' It was a really good day.