Dr. Lin X. Chen

    March 2005:

    Dr. Lin X. ChenDr. Lin X. Chen and I have worked in the same corridor for more than 15 years. While not in the same research group, we are well aware of each other's projects and have even co-organized a symposium at Argonne together (on in situ methods). Her research is fascinating and her work ethic indomitable. We took the excuse of this article to have an extended conversation about Lin's current research interests, what led her to science as a career, and what drives her now.

    Dr. Lin Chen's scientific career ranges from peptide synthesis to laser and x-ray physics, from bacterial photosynthetic reaction center proteins to semiconductor nanoparticles. Lin recognizes that many recent scientific breakthroughs rely on interdisciplinary research and she is known for her diverse scientific interests and capabilities. Her pioneering research on the time-domain combined laser and x-ray pulses method has established an entirely new approach for excited molecular structure determination. Although x-rays have been used for static molecular structure determination for almost a century, their potential to capture short-lived transient molecular structures remained untapped until recently. Dr. Chen has been leading a research project that successfully determined structures of short-lived molecular intermediates in solution after photoexcitation using light pulses from a laser with simultaneous x-ray pulses from the Advanced Photon Source at Argonne. This research requires knowledge of organometallic compound synthesis, the photochemistry of organic molecules, laser optics, and synchrotron x-ray methods.

    Featured in a Science article recently, Lin's work determined the structure of a photodissociated metalloporphyrin in solution with nanosecond time resolution. This particular molecule is an analog of the heme functional group that carries oxygen in myoglobin and hemoglobin, which relates to oxygen transport in blood. She also captured another transient molecular structure with a copper center that undergoes photoinduced electron transfer, resulting in a short-lived intermediate with a distinctively different structure from the ground state molecule. Probing these transient molecular structures has significant impact towards understanding the mechanisms of molecular interaction with light. These are essential processes in photosynthesis, molecular devices, and solar energy conversion and storage. A thorough review of Lin's work can be found in a 2004 issue of Angewandte Chemie, in which the abstract ends with this tantalizing statement, "By using other ultrafast x-ray facilities that will be completed in the near future, time resolution for excited-state structure measurements should reach femtosecond timescales, which will make "molecular movies" of bond breaking or formation a reality".

    Dr. Chen obtained her B.S. in chemistry from Peking University and then came to the U.S. to pursue her graduate education. Lin joined the University of Chicago Chemistry Department where she received her Ph.D. in 1987 in Physical Chemistry under the guidance of Prof. Graham R. Fleming. Her thesis projects involved protein dynamics using ultrafast laser spectroscopy and molecular modeling. Lin was awarded a prestigious NATO fellowship during that time. After this, Lin went on to perform postdoctoral research in the Department of Chemistry at the University of California at Berkeley with Prof. Herbert Strauss and Dr. Robert Snyder. There her work involved molecular dynamics of long chain alkanes and peptides using vibrational spectroscopy. Since 1989, she has worked in the Photosynthesis Group in the Chemistry Division of Argonne National Laboratory.

    Lin attributes her love of scientific research to her upbringing and deeply appreciates the support from her family and mentors. As the daughter of two organic chemists, Lin was inevitably exposed to scientific research from an early age. Although her parents never tried to make her a chemist, she was fascinated by the glassware and colorful solutions in her father's laboratory, and played with a wooden CPK molecular model set at home as a child. She thought the clusters of hexagons representing fused aromatic rings in her father's notebooks were beautiful tortoise shells. Later in her graduate career, she considered heself very fortunate to have Prof. Fleming (now at UC Berkeley), one of the pioneers in ultrafast molecular dynamics, as her advisor. He is not only a world-class scientist, but also an extremely effective mentor to his students. Lin found his research group to be a place where people with different backgrounds and strengths were able to flourish in their own way. This positive experience in graduate school encouraged her to pursue a career in fundamental research. Dr. Chen is married to another chemist, Dr. Di-Jia Liu, whom she met in Peking University. Their family includes daughter Victoria who was born in 1986 while Dr. Chen was a graduate student. 

    As a result of her experiences, Dr. Chen believes that many scientific accomplishments result from dedication and an innate thirst for knowledge. The multidisciplinarity of Lin's research exemplifies the way she thinks and approaches her work. As she learns more about the natural world through her research, Lin becomes ever more captivated by the way that sophisticated and beautiful molecules are organized in nature. One of her favorite quotes is from K. Hokusai, a famous Japanese painter: "All I have produced before the age of seventy is not worth taking into account. At seventy-five I have learned a little about the real structure of nature---of animals, plants, and trees, birds, fishes, and insects. In consequence, when I am eighty, I shall have made still more progress. At ninety I shall penetrate the mystery of things; at a hundred I shall certainly have reached a marvelous stage, and when I am a hundred and ten, everything I do---be it but a line or a dot-will be alive".

    — Written by Dr. Kathleen A. Carrado