Alexander Dalgarno: From atomic and molecular physics to astronomy and aeronomy

As Sir David Bates wrote in 1988, “There is no greater figure than Alex Dalgarno in the history of atomic-molecular-optical [AMO] physics, and its applications” (1). Prof. Alexander Dalgarno (Harvard) passed away peacefully on April 9, 2015 at age 87 in the presence of his long-term companion, Fern Creelan. Alexander Dalgarno and Ewine van Dishoeck pose by the statue of Albert Einstein outside the National Academy of Sciences headquarters in 2002. Image courtesy of Ewine F. van Dishoeck. During a career spanning 60 years, Alex produced about 750 publications covering a vast array of topics spanning all of modern AMO physics. His scientific accomplishments are so broad that even many people who knew him were only aware of a small portion of them. Alex’s development and implementation of new theoretical quantal methods, and his application of these to observations and experiments, led to about 200 publications in astrophysics and 100 in atmospheric science. Alex’s impact derived from the combination of his seminal insight and unparalleled, boundless, and sustained productivity. His long career is described in his autobiographical article “A serendipitous journey” (2) and in the books written in his honor (1, 3⇓–5). Alex, a twin and the youngest of five children, was born in London in 1928 and grew up during the Second World War. Despite the distraction of air raids, he did well in grammar school and enjoyed mathematics. Alex also excelled at sports, especially soccer, and was invited to try out for the Tottenham Hotspurs …