**In Memory: Martin Karplus—A Trailblazer in Theoretical Chemistry**
Martin Karplus, the theoretical chemist whose innovative work in computational chemistry garnered him the Nobel Prize in 2013, has passed away at the age of 94. His scientific contributions, particularly in the development of computational models for exploring complex chemical systems, have created a lasting impact in the fields of chemistry, physics, and biology. Celebrated as a trailblazer in chemical physics, Karplus revolutionized the approach researchers take to study molecular interactions, establishing the groundwork for contemporary computational chemistry.
**A Path from Vienna to Harvard**
Karplus was born in Vienna, Austria, in 1930. His childhood was dramatically altered when his family escaped the Nazi invasion in 1938. In search of safety, they initially relocated to Switzerland before ultimately finding a home in the United States. It was in Boston, where he pursued his education, that his early passion for science began to blossom—partly ignited by a microscope gifted by his parents.
Driven and intellectually curious, Karplus aimed for a career in biology but approached the field from a diverse perspective. Recognizing the necessity of a robust foundation in the physical sciences, he commenced his undergraduate studies at Harvard University in 1947, focusing on physics and chemistry. After completing his degree in 1950, Karplus sought mentorship from prominent figures in the scientific arena, including his elder brother’s advisor, physicist Robert Oppenheimer. Following Oppenheimer’s recommendations, he enrolled at the California Institute of Technology (Caltech) for graduate studies, initially concentrating on biology.
Nonetheless, the pursuit of science often presents obstacles, and a disagreement with his biology advisor led Karplus to shift gears toward chemistry. He became part of Linus Pauling’s research group, one of the most distinguished scientists of the time. Under Pauling’s guidance, Karplus earned his PhD in 1953, centering on hydrogen-bonding interactions of the bifluoride ion (FHF⁻)—a precursor to his later work in computational modeling.
**A Diverse Career in Chemical Physics**
Karplus’s academic pursuits took him from postdoctoral research at the University of Oxford to teaching roles at the University of Illinois and Columbia University, eventually establishing himself at Harvard University in 1965. Although his academic roots were firmly embedded in chemistry, Karplus’s work spanned a multitude of disciplines, embodying his intrinsic belief in the interconnected nature of scientific inquiry.
The 1970s emerged as a pivotal era in Karplus’s career. Together with his postdoctoral researcher, Arieh Warshel, he pioneered computational methods that integrated quantum mechanics with classical mechanics—an approach that facilitated highly precise calculations of molecular characteristics. Their hybrid techniques enabled modeling of intricate biological molecules, allowing researchers to gain insights into biomolecular behavior with unmatched accuracy.
At the time, their efforts met skepticism. Many experimental chemists doubted the practicality of computational methods, while biologists questioned their relevance. However, Karplus and his team persevered, convinced that their approaches would transform molecular understanding. By the 21st century, their contributions became indisputable. Today, thousands of computational chemists utilize techniques inspired by Karplus’s foundational work to simulate phenomena ranging from enzyme kinetics to drug interactions.
This research in molecular dynamics ultimately earned Karplus the Nobel Prize in Chemistry in 2013, shared with Arieh Warshel and Michael Levitt. The Royal Swedish Academy of Sciences acknowledged their “development of multiscale models for complex chemical systems,” solidifying Karplus’s reputation as one of the most significant chemists of his generation.
**Beyond Molecular Dynamics: Varied Contributions**
Karplus’s pivotal contributions to computational chemistry constituted only one facet of his diverse career. He made remarkable advancements in nuclear magnetic resonance (NMR) spectroscopy, particularly through the establishment of what is now referred to as the *Karplus equation*. This equation elucidates the connection between dihedral angles in a molecule and NMR coupling constants, serving as a vital resource for chemists investigating molecular structures.
Mentorship was another crucial aspect of Karplus’s professional life. Over the years, he guided and inspired over 250 researchers, many of whom emerged as leading figures in computational and theoretical chemistry. His commitment to nurturing young scientists ensured that his innovative spirit and methodologies would sustain through the generations that followed.
**A Life Beyond the Laboratory**
Martin Karplus was far from being the conventional scientist isolated to the laboratory. Outside of equations and digital simulations, he pursued two unique passions: cooking and photography. During summers spent in France and Spain, he delved into the culinary arts, working in eateries and enhancing his understanding of food’s cultural importance. Concurrently, his photography revolved around vanishing lifestyles worldwide, encapsulating the beauty and delicacy of disappearing traditions. His photographic endeavors have been showcased in various exhibitions, offering insight into his artistic inclinations.
Karplus