Professor Eckhardt set to retire after 50 years of service to Nebraska Chemistry

Photo Credit: Eckhardt Retirement Reception
Wed, 04/26/2017 - 16:32

Professor Craig Eckhardt’s first lab, tucked away deep within the walls of Avery Hall, was no bigger than his current office. On a good day, it may have measured 300 square feet.

It wasn’t as bad as Professor Lawrence Parkhurst's, where they converted the men’s room for him, Eckhardt said.

It didn’t take long for Eckhardt to move into an office with a better view. He only spent about two years in Avery before moving to the fifth floor of Hamilton Hall – his home for the next 47 years. And after spending half a century exploring the mysteries of chemistry from that lab, he has decided to call it a career at the University of Nebraska – Lincoln. A place that wasn’t even a part of his initial plan.

“I had a postdoc with a world-famous spectroscopist at MIT named John Lord, and I had that all lined up,” Eckhardt said. “I had applied to Nebraska at the persistent urging of my research advisor, but I thought that a postdoc was necessary for an academic post.”

Eckhardt had more or less forgot about Nebraska while he was wrapping up his dissertation at Yale University, until he received a phone call from Professor Gordon Gallup inviting him out for an interview.

At the time, he wasn’t aware that the department had received a multi-million dollar developmental grant from the National Science Foundation, nor was he aware of the new eight-story facility being constructed. When he considered the ability to design his lab and to purchase all the equipment he would need, the offer seemed too good to be true.

“It pretty much was an offer one could not refuse,” he said.

And the rest is history.

One of Eckhardt’s earliest projects at Nebraska was focused on piezomodulation spectroscopy. It was a new kind of spectroscopy he wanted to develop for molecular solids that looked at how the electronic structure of the molecules and the crystals which they comprised was affected by stress and strain placed on the crystals.

Eckhardt became interested in the topic after reading physics literature, where he noticed that the problems of measuring critical points in metals that faced physicists of the day was not unlike those confronted by molecular spectroscopists dealing with crystals of molecules that had high light absorptivity.

“You could get a crystal of a dye molecule, and you would dissolve it and get, say, a beautiful blue solution. But you would form the crystal, and you would look at the crystal, and it would look like copper metal. Literally look just like copper. So how in the heck did it go from this one thing to the other?,” Eckhardt said.

Crystals of certain molecules, mainly dyes, become highly absorbent and reflect light like a mirror over an extensive region of two to three electron volts of light energy. Over this range, the crystals lose any kind of structure, thus preventing access to a wealth of information about the electronic structure.

The physicists confronted this by subjecting metals to stress and strain where they could experimentally identify critical spectroscopic structures associated with so-called Van Hove singularities that are vital to interpreting the theory of the electronic structure of the metal. This paralleled the problem with the highly reflective dye crystals, so Eckhardt adapted a similar approach to molecular crystals to unravel the electronic interactions and structure in these high reflectivity molecular crystals.

“So really what I wound up being interested in was how the molecules talk to each other, electronically,” he said.

It was an interest that sat at the core of many future projects, and it was this constant questioning of the building blocks of intermolecular forces that drove Eckhardt’s career.

In 1979, Eckhardt was awarded a John Simon Guggenheim Fellowship. The Guggenheim is one of many – albeit the most prestigious – accolades that fill his resume. He is only one of four Nebraska Chemistry faculty members to ever hold this prestigious fellowship. He has also received a Fulbright Senior Fellowship and several German Academic Exchange Fellowships (DAAD). These fellowships placed him at the heart of intermolecular research at institutions like Cambridge University, Johannes Gutenberg University, the University of Milan (La Statale), Technical University of Wroclaw, and Pohang Technical University. All far from the Black Hills where he was born.

“I’m a southern gentleman,” Eckhardt said with a smirk. “I was born in South Dakota.”

From the Black Hills, he and his family moved around the southern United States as a child during WWII, as his father was a civilian worker for the United States Army. After the war, his family moved to Denver, where he spent his childhood, and where his father worked for the Atomic Energy Commission. It was during this time that Eckhardt started to develop a curiosity toward science.

More specifically, it can be traced back to the kitchen.

“My mother was an excellent and inventive cook. I would watch her concoct these things, and I would watch her put this goo into a pan, put it in the oven, and out you would get a cake,” he said. 

This transformation, and many others, seemed almost magical, but his mother could offer no explanation for why it happened.

It was the lack of an explanation that sparked his interest in the transformation of matter.

“There were all kinds of mysteries I knew had to have a reason,” he said. “My dad’s mantra was that there was a rational and nature-based reason for everything, although we may not know it.”  

His curiosity brought him to the University of Colorado Boulder, where he was elected to the university’s Phi Beta Kappa chapter. He graduated magna cum laude in 1962 and then went on to Yale, where he earned his master’s in 1964 and his Ph.D. in 1967.

Throughout his career, Eckhardt continued to address unresolved questions of chemistry, particularly those which dealt with solid state chemistry.

In particular, he looked at problems that were associated with a compound called distyrylpyrazine (DSP).  The puzzle was that if DSP was in a crystalline state and irradiated with light at wavelengths greater than 400 nanometers, one would get oligomers, or short polymers. When the wavelength was greater than 400 nanometers, high-polymers were produced. However, irradiation of DSP in solution showed no such wavelength dependence.  Nobody had a sufficient explanation. So, he set out to find out what has going on.

Eckhardt suspected that it had to do with how the molecules “talked” to each other electronically in the solid state, Exciton Theory. He found that through solid-state electronic and Raman spectroscopy studies, that an excitonic mechanism was the explanation for the wavelength dependency.

He always sought to explore questions that received little attention during his career, and while it was research like that focused on DSP that kept him interested in chemistry, it was his students that made him love it.

Words do no justice for the feelings Eckhardt has for his graduate students, but asked to explain, he tried his best to articulate what their relationships mean to him.

“I enjoyed them more than I did the research,” he said. “I truly had a remarkable group of graduate students.”

Again, words alone aren’t enough.

Many of his students had never heard of the type of research he was conducting before enrolling in Nebraska Chemistry’s graduate program, but Eckhardt said they seemed as fascinated as he by the area, and they put their hearts and souls into it. In return, he tried to create an environment where his students, could make mistakes with no repercussions, but would learn from them. He wanted them to take pride in- and ownership of their work.

“It was their baby, so I wasn’t going to tell them what to do the next day,” Eckhardt said. “I don’t believe you teach someone to walk by holding them up all the time.”

Over 50 years, Eckhardt advised 25 students to Ph.D.’s, and they have gone on to have successful careers, many of which aren’t closely related to their Ph.D. work. His students have gone on to become directors of research at large companies and as established faculty members in the scientific community. One even became a professor of epidemiology.

Eckhardt told all his students, “When you walk out the door with a degree, you’re my peer. You’re going to be a functioning, independent scientist.”

Many of Eckhardt’s peers also forged relationships with him that went deeper than science

“He is a great colleague, a great mentor, and an outstanding scientist,” Nebraska Chemistry Interim Chair Professor Jody Redepenning said. “But, he is also a dear friend.”

His relationship with his students and fellow faculty was one of understanding and one of respect. But at the root, was a longing for understanding of pertinent problems in solid state chemistry.

All the research conducted in Eckhardt’s lab tried to answer the question that, to him, still rests on the frontier of chemistry today.

“They all dealt with what I consider to be the real frontier of chemistry now, and that is the codification and quantification of intermolecular forces,” Eckhardt said.

In one way or another, his projects addressed different facets of this question.

“There has not been a systematic, quantitative investigation of intermolecular forces. One has to formulate some very simple models that many find – both boring and unexciting – and analyze the data in detail such that there is reliable predictive power before moving on to the complex,” he said.

And though Eckhardt is stepping away from his life-long investigation, he feels he is leaving a department that is moving in a good direction.

“I came to this department when it was kind of a sleepy, little, good department on the prairie. And now, it’s becoming a powerhouse,” he said.

Stepping away from Nebraska Chemistry at a time of great growth isn’t easy, but Eckhardt has some other goals he wants to accomplish. He’s a student of the world and still has a list of places to visit.

High on that list is Antarctica.

The only continent he hasn’t seen.

“It’s the closest I’ll probably ever come to visiting a different planet,” he said.

Closest to a different planet, and a far cry from that make-shift lab in Avery it all started in 50 years ago.

Eckhardt’s official last day with Nebraska Chemistry will be Aug. 31, 2017.