From Appalachia to astrophysics: Fifty years of experiments by Chemistry alum Barney Ellison

Charlyn Paradis
portrait of person

Barney Ellison

For over 50 years, Barney Ellison ’74 Ph.D. has been at the forefront of experiments involving radicals – a highly reactive chemical species essential for processes like combustion.

The nature of his work is intense, involving the handling of unstable compounds, high-pressure techniques, powerful lasers, and extreme voltages.

Ellison himself is a dynamic presence in the field, with a robust career spanning five decades and a tireless passion for continuing chemistry research.

He has developed detailed experimental methods that have become standard resources for scientists studying atmospheres affected by combustion fumes, fires, and weather, as well as those exploring the formation of molecules in space.

Early Life: Texas to West Virginia to Connecticut

Ellison was born in an army-base town in Texas to a nurse mother and a physician father, who was a casualty of World War II. After the war, his family moved to West Virginia, where his mother remarried.

Ellison grew up on a small farm in rural Appalachia. Instead of playing with chemistry sets, he competed in statewide cattle competitions, showing his sheep and cows, once winning 1st place for one of his heifers.

The local jobs of coal mining and steelworking did not appeal to him. He wanted to study science, and when it was time to head off to college, his mom had heard of Trinity College in Hartford through the church. As Ellison says, “I was an early beneficiary of affirmative action. Nobody from Appalachia comes here.”

During his time at Trinity, where he majored in biology, Ellison created his signature look of always wearing a bow tie. He recalls, “If you didn’t wear a tie, you couldn’t get into the dining hall.” Since a long tie is impractical in a lab, he learned to tie a bow tie and never looked back.

Life at Yale

When he came to Yale in 1965, Ellison matriculated in the Department of Pharmacology because he wanted to understand how penicillin worked. After two years, he switched to the “easier subject” of chemistry. He studied organic chemistry under the supervision of Professor Kenneth Wiberg and earned his Ph.D. in 1974.

The campus in the ‘60s and ‘70s was a place where activism and research co-existed. The Vietnam War was going on, as was the trial of the Chicago Seven, with one defendant being chemistry classmate John Froines ’67 Ph.D. Ellison recalls when a group marched up to Science Hill and yelled, “Scientists, what are you doing? Get out of your labs. Join the revolution!”

But he was more interested in studying these very small, highly reactive, unstable molecules called radicals. They play a crucial role in atmospheric chemistry – influencing air quality and ozone levels – and are believed to be central to the formation of molecules in the interstellar medium (space between stars and galaxies). This latter finding wouldn’t happen for another 50 years – something Ellison would learn at the culmination of his life’s work.

In the early days in the Wiberg Lab, he was focused on the fundamental research of radicals. What is the absolute energy? What is their exact shape? How do they react?

“They react in very precise ways. For example, when you drive a car, the gasoline ignites a spark,” he explains. “When the gasoline breaks down, it breaks apart into these radicals to begin reacting with 02. For a split second, your engine is full of an uncountable number of these radicals. These radicals are what generate the heat and power, and so on. So, it’s important to know the shape of the radicals and their electron distributions. We set out to directly measure these things.”

In the Wiberg Lab, Ellison performed many measurements, something he said is very hard to do and most people don’t do anymore. They rely on calculations instead.

The Department recognized his (two volumes!) doctoral thesis as the best of his graduating class by honoring him with the Wolfgang Prize. 

three men standing near machines

Ellison (far left) with Paul Engelking (Chemical Physics) and Kevin Peters (Organic Chemistry) in 1972 in the Kline Chemistry Laboratory, surrounded by equipment necessary for performing measurements.

While at Yale, he interacted with people from a variety of research groups. He attended physics seminars to learn the language of physicists, which proved very useful as he was soon to be surrounded by them.

Life’s Work: The Yale - Colorado Connection

After receiving his Ph.D., Ellison took a postdoctoral position in Bill Reinhardt’s group and was soon conducting experiments in Carl Lineberger’s lab at the Joint Institute for Laboratory Astrophysics (JILA) in Boulder, Colorado, where, as the only chemist among physicists, he introduced an organic chemistry focus for developing ion chemistry methods.

two men, a dewar, and large machine

Ellison (left) in 1975 with a fellow postdoc, Paul Zittle, at JILA, standing next to his sample that blew up in a metal-encased dewar.

Ellison recalls having to use explosive samples for some of the ion beams that they interacted with lasers. “These were hard experiments, and it was very easy to make a mistake.”

Following his postdoc, Ellison joined the faculty in 1977 in the Department of Chemistry at the University of Colorado, Boulder (CU-Boulder), and has been there ever since.

In addition to teaching undergraduate chemistry, he developed a research program to study reactive intermediates in organic chemistry using advanced technologies like customized mass spectrometers designed to follow reactions and characterize the fleeting species using laser spectroscopy. Through a large number of experiments, he has characterized the intrinsic properties of radicals, carbanions, and cations. These intermediates control the chemistry involved with combustion engines, the atmosphere, and continental aerosols, which trigger cloud formation.

In Boulder, he had the added benefit of having both JILA and the National Oceanic and Atmospheric Administration (NOAA) – “the weather guys” – as neighbors. They were applying molecular physics to atmospheric processes.

And so began a decades-long collaboration among the experimentalists of three institutions – JILA, NOAA, and CU – and the convergence of chemical physics and mechanistic chemistry to understand atmospheric processes.

They integrated negative ion photoelectron spectroscopy and flowing afterglow techniques to test experimental methods of studying reactive intermediates. One such example is benzene, which is in the gasoline in your car. They measured some of its most fundamental energy properties, such as ionization energies, electron affinities, and gas acidities. Working with theorists, they refined and validated the data to achieve accurate measurements. Their findings are in tables maintained by the National Bureau of Standards, which are widely used as a reference by academics, scientists, and engineers.

“I met Barney Ellison upon entering Yale in 1973 as a graduate student. Barney was the leader and advisor for us, always ready to talk about science,” said Veronica Vaida ’77 Ph.D., Yale Chemistry alum and professor emeritus of chemistry, CU-Boulder. “Later, I have been his colleague at the University of Colorado in Boulder for over 40 years. Our interactions, inspired by atmospheric measurements, a suggestion by Adrian Tuck (NOAA), and Barney’s love of reactive organic intermediates, led to our development of a model for atmospheric aerosols, which pointed the way for both fundamental research and applications to atmospheric chemistry and climate. Most of all, it was and still is great fun having coffee and a chat with Barney.” 

Ellison’s more recent experiments aim to address excessive carbon produced from biomass burning and smoke and soot produced by internal combustion engines and wildfires.

In the 50 years he has been in the radicals field, Ellison has seen them become more prevalent, from the hazardous polycyclic aromatic hydrocarbon chemical compounds found in the air, soil, and water to the building blocks for more complex molecules in interstellar chemistry.

Impact and Legacy

Although he retired from teaching in 2013, he continues to collaborate with research groups at the University of Florida, Argonne National Laboratory, and Harvard’s Center for Astrophysics.

three people near synchrotron

Ellison, a graduate student, and late Prof. John Stanton, collaborating partner of 30 years, standing in front of the beamline at Berkeley’s Advanced Light Source, a $100M synchrotron. (2013)

He has been recognized for his exceptional talent through the following awards: an NIH predoctoral fellowship, the Wolfgang Prize, an Alfred P. Sloan Foundation Fellowship, and a John Simon Guggenheim Fellowship.

Ellison’s passion for continuing chemistry research at Yale inspired him to launch a fundraiser in 2011 to establish the Wiberg Fund for the Department.

On several occasions, he has returned to New Haven as a guest lecturer. In the spring of 2024, he gave the Johnson-Sessler Lecture as Yale Chemistry marked the 100th anniversary of the Sterling Chemistry Laboratory.

Mark Johnson, the Arthur T. Kemp Professor of Chemistry at Yale, who invited Ellison to lecture, had this to say. “I first met Barney at a party in Cambridge, somewhere around 1979. He made a lasting impression with his passion for getting to the core of chemistry by all means possible. I followed him in the Lineberger group at JILA and was profoundly influenced by him in choosing directions for my research at Yale. A breakfast visit with him at Dot’s Diner remains a must on every visit to Boulder.”

During the lecture, Ellison spoke about his work, the advancements in the field over the years, and the challenges ahead.

“As we’re steadily working out the properties of these reactive intermediates, theoretical chemistry is rapidly evolving,” he said. “Since I left Yale in 1974, electronic structure calculations have become extremely powerful. The development of new computing resources – just staggeringly powerful computers – but equally as important, new algorithms and software packages mean that if we, the experimentalists, give the theorists a reliable pool of experimental facts for these radicals and ions, these guys can really create accurate predictive models for complex processes.”

“People in my generation are fading away,” he said. “The experiments are hard to do.”

Yet, “How do you know something is true?” he posits. “Somebody has to observe it. You have to do an experiment. If you don’t do an experiment, nobody believes it. And so, it turns out, the arrow-pushing education I got at Yale is very powerful and, used in that way, is a very good guide.”

At 82 and having been retired for over a decade, Ellison shows no signs of “fading away.”

“Nowadays, I still do chemistry, and I’m now working with astronomers. In the fall, we may go out to the NASA Jet Propulsion Lab at Caltech and do experiments. I think I know how benzene is formed in space.

And so, all my life, I’ve been going forward. You never look over your shoulder. There’s a famous quote by the great pitcher Satchel Paige. ‘Don’t look back. Something might be gaining on you.’ So, I just keep running.”