Physical Chemist Peter O’Donnell Offenhartz spends his summers on a small island off the coast of Maine. Knowing that he’s a scientist and creative problem-solver, people there come to him with requests that run from “How can I improve my telephone service?” to “Why does my boat battery keep failing?” Read on to find out how Offenhartz uses his knowledge of chemistry and physics to help his neighbors.
“I think I always knew I was going to make my living in science,” says Offenhartz, who grew up in Westchester, outside of New York City. His parents “wanted me to be a doctor, of course.” But experimenting with a chemistry set and building a shortwave radio inspired Peter to choose research over medicine.
At Swarthmore College, “I took freshman chemistry and I took freshman biology and I didn’t like biology at all” because it required “too much memorization.” He also tried physics out that year, enjoying the subject but struggling with it because he had not yet studied the advanced math that would help him. “Chemistry was the one thing I did best at, so I went on to graduate school in chemistry.”
Also at Swarthmore, Offenhartz met Barbara Hopf, a fellow chemistry major. Like Peter, she was minoring in mathematics and physics. The couple went on to get their doctorates in physical chemistry at the University of Pennsylvania and to postdocs in England and Japan.
Back in the U.S., Offenhartz (Peter) also did postdoctoral work at Harvard, with Martin Gouterman, working on porphyrins.
You might not think that animals and plants have much in common. But we both breathe, taking in carbon dioxide (plants) and oxygen (animals). We use those gases to produce the energy we need to stay alive. On a molecular level, another thing we have in common is porphyrins, which also make us (plants and animals) colorful.
Offenhartz explains that a porphyrin is “a very big organic molecule with a metal at the center.” There are porphyrins in the hemoglobin which carries oxygen in your blood and makes it red. And chlorophyll, which makes plants green and helps them create energy is also “effectively a porphyrin.”
In addition to working with Gouterman, Offenhartz worked with his wife, Barbara, on corrin compounds, which she had studied for her PhD. He had been using computers to calculate molecular energy levels — the orbitals of electrons in atoms within molecules. Peter and Barbara combined forces to calculate the molecular orbits of corrins.
After winning a grant from the National Science Foundation, Offenhartz headed to France, where he solved “the 10Dq problem.”
Electrons move in an orbital around each atom’s nucleus. The more electrons an atom has, the more suborbitals they form, moving in shell-like paths around the center of the atom (its nucleus).
These suborbitals have letter names including s, p, d, f, and g. Solving the 10Dq problem helped scientists better understand the placement of electrons and therefore the energy states of ligands — molecules that bind to a central metal atom like iron, zinc, and cobalt. Before Offenhartz approached the problem, scientists had evidence that there was a certain energy difference between the d suborbitals. But when they tried to prove that this energy difference was the right one, their calculations came up with another number — not the one they had observed to be correct. Offenhartz figured out what they were doing wrong and calculated / proved the correct difference (10Dq).
He went on to work for different companies, investigating ways of improving the development of alternative sources of energy such as geothermal heat and solar electricity. How might one make geothermal steam cleaner? And how might one store thermal and solar energy? Heating a huge tank of water was inefficient: what other methods might work? These were the kinds of questions Offenhartz investigated.
The physical chemist also worked on aerospace batteries — batteries rocketed up to Earth’s atmosphere on satellites. “Those batteries were crucial to early satellite technology.” When traveling through bright times of day, satellites are powered by solar energy. But “when you put a satellite into orbit, you have to put a battery in it because the satellite goes into shadow for a certain amount of time each day and can’t use solar [power].”
His understanding of the chemistry and physics behind batteries would help a neighbor on that island where Peter and Barbara Offenhartz spend their summers. The neighbor’s boat’s battery kept dying. He replaced it a couple of times before Offenhartz considered the problem from a scientific perspective.
“I realized that he had water in the bilge” (the lowest area of a boat, where its sides meet below sea level). “Every physical chemist knows that salt water conducts electricity,” potentially draining a battery. So “I said, ‘Frank, pump it out. Just pump it out.’”
“Finally, he pumps it out and nothing happens and I’m talking to some guy and saying ‘Watch this. You’ve got to watch this. It’s going to start.’” Offenhartz asked Frank to start the boat’s engine again. “And it started!” Removing the water from the boat’s bilge solved the problem.
Only two people live year-round on that island. Until the early 21st century (the early 2000s), they relied on marine radios to communicate with people on the mainland. Cell phone technology was becoming available but was still quite expensive. So the islanders “asked about a cheaper way to get a telephone in [their] house.” “Spread-spectrum telephones were just coming onto the market. We found a kitchen telephone that was in fact spread-spectrum. It was 1.2 Gigahertz….” But would that phone’s signal reach across the bay to the home of a friend who had offered to let the couple use his house to connect with a mainland telephone?
“I thought ‘It’s too far,’ but then I thought maybe you can build an antenna that’s directional and will point” to the island. Offenhartz designed the antenna and put it on the mainland, in the house of that friend.
Then “Bob and I got in his boat checking, checking, checking” the signal on the spread-spectrum phone as they crossed the bay over to the island. “And I still had a dial tone when we got into their house.” When Math4Science spoke with Offenhartz, he told us that the couple “still have some kind of military spread-spectrum phone in their house.”
Impressed with the advantages of spread-spectrum communication, which is digital and uses “10 different channels of communication, more or less all at once,” Offenhartz looked into who had the patents on it. When he was told to “look into QualComm,” “I went out and bought $5,000 worth of shares, which turned into $100,000.”
From short-wave radio to spread-spectrum communication, Offenhartz has enjoyed and profited from his curiosity about how things work.