Fall 2002

Honoring A Quantum Leap

It’s hard to keep a good idea down.

That’s how Ernest Davidson sees his groundbreaking research that paved the way for the development of computational quantum chemistry, now the standard tool utilized by chemists worldwide to better understand the nature of matter. The process makes it possible to model chemical reactions and the response of molecules to radiation.

Earlier this year, Davidson, a 1958 chemical engineering alumnus, became the first quantum chemist and first Rose-Hulman graduate to receive the National Medal of Science from President George W. Bush at a special White House ceremony. The National Medal is the nation’s highest award for lifetime achievement in the fields of scientific research. Fred Garry, ’51, received the National Medal of Technology in 1990.

"Each of these individuals has helped advance our country’s place as a leader in discovery, creativity and technology," President Bush stated about this year’s 15 Medal award winners. "Their contributions have touched all of our lives and will continue to do so."

The award validated Davidson’s long personal and professional struggle to convince scientists and researchers to use computer software to model chemical properties. At one time, chemists dismissed the field and suggested that the National Science Foundation stop funding research. Other experts in quantum theory preferred a pen and paper approach and dismissed computing as "anti-intellectual."

"Personally, the National Medal meant that what I had done for the last 40 years was useful. It was the first major award from outside my peer group of scientists," Davidson said. "My role was to ignore critics and plow ahead until the field really became useful and was accepted."

Davidson is now held in the highest regard with NSF, and a 2001 international conference on "Molecular Quantum Mechanics: The Right Answer for the Right Reason" was conducted in Davidson’s honor.

"No other quantum chemist has shown the diversity of important developments," noted an NSF statement about Davidson’s significant accomplishments.

Davidson’s idea was to combine his love of chemistry and mathematics, nurtured as the son of a high-school science and math teacher. He thought that molecules and chemical reactions could be modeled, through computational methodology, to aid in the explanation of experimental data. His research started at Indiana University in 1958, shortly after graduation from Rose Polytechnic Institute, and a time when digital computers were arriving on university campuses.

The Schrödinger equation that forms the basis for describing the structure of matter had been discovered in 1925. Formal mathematical properties of solutions to this equation had been developed, but closed-form solutions for real physical systems of interest to chemists were not possible. There were fewer than 100 experts in the world in applications to chemistry, and almost all of these were using qualitative methods and avoiding numerical results. There were only five or six centers in 1958 that were trying to use digital computers to extract numerical approximations to the solution.

In 1962, Davidson moved to the University of Washington and his research group, along with a few others around the world, developed the basic methods for obtaining numerically accurate approximate solutions to the Schrödinger equation for the electrons in molecules. By about 1980, some researchers spoke of the "new age" of quantum chemistry, when quantitative results for small molecules became as accurate as provided through experimental means.

The obstacles were many, according to Davidson. Computing was very expensive and no one could afford to pay the cost that university computing centers wanted to charge (Davidson’s formal bill from the UW computer center was often over $1 million per year); computing was extremely cumbersome, with small memories and low reliability; and American graduate students with a typical bachelor of science degree in chemistry lacked the mathematics skills to make contributions to this field.

"The more interesting obstacle was that no one knew how to use computers for this purpose," states Davidson, the only Rose-Hulman graduate named to the prestigious National Academy of Sciences. "So we had to develop approximate methods, develop numerical algorithms, and then turn these algorithms into efficient computer programs. Some of my most cited work deals with how to compute the eigenvalues of very large matrices and how to evaluate billions of integrals efficiently – hardly what you would expect a chemist to do."

Today, computational chemistry (non-quantum) is a large industry, with molecular modeling being used in biological applications. It is now much easier to synthesize new compounds and easy to do a calculation on a hypothetical molecule that does not yet exist.

"What is hard is to think of what molecule should be made or studied," suggests Davidson, who is associate editor of the Journal of Chemical Physics. "The real issue for the future is to couple theory with artificial intelligence in order to allow computers to discover new compounds with designated properties. A new field called ‘chemical informatics’ is still in the process of being defined and is not respected by chemists. I guess that rather than resisting chemical informatics, chemists need to figure out how to make it work."

Davidson’s own research has moved more toward inorganic reactions and structure. He is developing methods for describing molecular magnets, generally large molecules containing several transition metal atoms.

Science has always played a large role in Davidson’s life. As class valedictorian at Terre Haute’s Wiley High School, he won a chemical contest conducted by the Wabash Valley section of the American Chemical Society. Rose-Hulman professors Oran Knudsen and Frank Guthrie encouraged Davidson to attend Rose Poly, and a full scholarship paved the way for his undergraduate education in chemical engineering.

"My education at Rose Poly provided a superior background in applied mathematics, numerical analysis and physics," he concedes. "Mechanical drawing has been an enormous aid in visualizing objects in 3-dimensions and in making freehand sketches. Practice in solving numerical problems prepared me for solving the harder numerical problems of quantum chemistry.

"Most important, a quantitative engineering attitude led me to view molecules as complex mechanical systems whose properties were computable," continued Davidson, who received an honorary doctorate of engineering degree from Rose-Hulman in 1998. "This was the real revolutionary concept to chemists but seemed a natural approach to me with my engineering training. It is still a view that students with a traditional chemical education find hard to accept."

Davidson earned a doctorate in chemistry from IU in 1961, and followed that with an NSF-sponsored postdoctoral fellowship at the University of Wisconsin. He then enjoyed a 22-year career on the University of Washington’s faculty before returning to Indiana in 1984 as a chemistry professor at IU. He served as academic department chair from 1999 until his retirement in June.

Today, at 65 years old, Davidson splits time between research professorships at the University of Washington and the University of North Carolina, as he and his wife, Reba, seek to be closer to their children and grandchildren in both areas of the country.

"The National Medal of Science has not had any immediate effect on my life . . . My reaction was one of surprise," Davidson modestly stated. "I felt I was worthy of the Medal, but an element of luck had to be involved."