Daniel J. Leopold

January 25, 1954December 10, 2015
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Daniel Joseph Leopold, PhD

1954 - 2015

Daniel J. Leopold, a long time resident of St. Louis and a physics research professor at Washington University, passed away on December 10, 2015, at home with his family at his side after a battle with pancreatic cancer.

Dan was born in Buffalo, NY on January 25, 1954 to Donald and Ruth Leopold, one of four children. His family moved to Rochester, NY where he completed high school at Fairport High school, earning their Top Science Student award. He completed his Bachelor’s Degree in physics at the Rochester Institute of Technology, while working full-time as a movie theater manager and, later, interning at Xerox Corporation in Webster, NY. His interest in condensed matter physics, sparked at Xerox, led to a Ph.D. in Physics from Washington University, a summer at Xerox Palo Alto Center in California and a postdoctoral appointment in the Physics department of Harvard University.

While in graduate school at Washington University, Dan met and courted fellow physicist Mary F. Muldoon from Chicago; they married in 1985. Together they raised two sons, James E. Leopold and Jonathan V. Leopold.

Beginning in 1985, Dan worked in the Research Laboratory of McDonnell Douglas Corporation. Using their Molecular Beam Epitaxy (MBE) facility, he designed, made and tested novel semiconductor materials. In 1994, he joined the Washington University department of Physics, where he set up a new MBE facility and laser lab. There he joined with Professor James Buckley in the development of new types of detectors based on Gallium-Nitride semiconductors for applications to high-energy physics and astrophysics. His recent work resulted in a discovery of the unique properties of amorphous semiconductors, and the development of new device fabrication techniques that are currently being applied to the development of very sensitive light detectors. This work has potential benefits in a number of areas of science ranging from new experiments aimed at the detection of Dark Matter to biomedical imaging. He leaves his Washington University team to complete the work of applying this transformative technology to new experiments that will help understand the nature of the cosmos and new devices that could aid in the diagnosis and treatment of diseases like cancer.

Dan was an enthusiastic amateur astronomer and amateur economist, but he was most passionate about muscle cars and drag racing. His 1992 Camaro stocker was a frequent sight at regional and national races, for which he and brother Mike would spend months of meticulous consultation and preparation to slice tenths of a second off their ¼ mile times. He single-handedly transformed the once daily-driver Camaro into a fully qualifying NHRA/IHRA stock car, compliant with all the rules and regulations that accompany that designation. He could rebuild a top and bottom end, weld a roll cage and tune an engine with little thought. He had all the tools for these jobs and more. Consequently, his garage and basement are disaster areas.

Dan is preceded in death by his Father, Donald J. Leopold, and is survived by his wife of 30 years, Mary M. Leopold (Muldoon), sons James E. Leopold and Jonathan V. Leopold (Tracey R. Leopold) of St. Louis, Mother Ruth M. Leopold, brothers Donald H. Leopold (Julie J. Leopold) of Los Angeles, Michael J. Leopold (Kimberly A. Leopold) of Indianapolis, sister Katharine A. Maysuch (Thomas M. Maysuch) of Rochester, mother-in-law Mary E. Muldoon, and thirteen much-loved nieces and nephews.

The family would like to express deep gratitude for the care of oncologist Dr. Kian Lim, and for the kindness of the Nerinx Hall community.

Visitation will be held Friday, December 18, from 4:00 p.m. until 8:00 p.m. at Kriegshauser Mortuary, 9450 Olive Boulevard, St. Louis, MO 63132. A Celebration of Life mass will be offered on Saturday, December 19, at 11:00 am, at St. Richard Catholic Church, 11223 Schuetz Road, St. Louis, MO 63146. A luncheon will follow at Orlando Gardens Event Center, 2050 Dorsett Village Plaza, Maryland Heights, MO 63043.

Dan was a faithful member of St. Richard Catholic Church. In lieu of flowers, the family asks that contributions be made to Catholic Charities of St. Louis.


  • Visitation Friday, December 18, 2015
  • Mass of Christian Burial Saturday, December 19, 2015

Daniel J. Leopold

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Harry Ringermacher

December 21, 2015

I am shocked to hear of Dan's passing. We were grad student colleagues. I always stopped by to look him up whenever I visited WU Physics. In fact I was there last year. I really liked Dan and we always had interesting things to talk about. He was a brilliant experimentalist and I loved to visit his working lab. I will miss him very, very much. My condolences to Mary.

Jill Andrew

December 20, 2015

My thoughts and prayers are with you.

Gloria Haberkorn

December 19, 2015

Dan and his family are in my thoughts and prayers. Dan was a kind and thoughtful nephew, always willing to help. He was intelligent but not boastful. He will be missed.

Terry Dannehold

December 18, 2015

I am very sorry to hear of Dan's passing. We went to grad school together. He was a good guy. My condolences to Mary and the rest of his family.

Paul, Aaron, Adam, & Alec Koppel

December 17, 2015

Dear Mary and family-

I am very sorry. My prayers and thoughts are with you.

Amir Jafarian

December 17, 2015

Dan the man Leopold. One of the smartest individuals I've ever met. Never encountered a question he couldn't answer and give a detailed explanation to. I have a breadth of fond memories having grown up with the Leopold boys. One of my favorite memories was watching Jimmy repeatedly rub his belly and call him 'Papoose' (this went on for a summer or longer). A normal person would think Jimmy was crazy and shoo him away, or at least get agitated, but he just had this content wide grin on his face. An exceptional man by international standards. Much love Mr. Leopold!

Betsy Wiard

December 16, 2015

With heartfelt sadness. So hard to believe. So many family memories. He will leave a great void in the lives of those that knew and loved him. Such a remarkable person.

Susan Muldoon

December 16, 2015

I will always remember his calm and steady way, his gentle kindness, his humor and his dimples. He will be deeply missed by many. My thoughts are with you all.

Kurt Haberkorn

December 16, 2015

For as long as I have known my cousin Dan, I have known him to have a quiet leadership quality about him which people willingly responded to. I remember foot races with Dan and his brothers at their home in Buffalo. Don was much younger and Dan changed the rules so that the slowest runner would win. He got upset when everyone started going real slow. Then we went to the corner store and bought wax face candy. After Dan's family moved to Rochester, my family would visit and when it came time to leave Dan and the boys would hid me to help delay my leaving. It was great fun.

I discovered Dan had a addiction for curiosity and figuring things out. This graduated from cars, combustibles and finally science and physics. As I have said before, Dan taught me things I did not know, I didn't know. In doing so, he enriched my life, and will always be a part of me. He will be missed by many.

Though he is with the Lord God now, my thoughts and prayers continue go out to Dan, and his family.

December 15, 2015

May Dan's memory be our blessing.
the Jappa's