A Genial Enthusiast of the Very Brief
By Rich McManus
On the Front Page...
Tininess can be taken to several powers, advancing past petite to teensiness, then teensy-weensy, and on into the realm of nano, pico and femto. No, these are not the names of undocumented Marx Brothers, but rather measures of time and space. According to Le Système International d'Unités (SI), nano (billionth) is relatively obese compared to pico (trillionth), which is a thousand times smaller, but still larger than femto, which is one millionth of a billionth, or a quadrillionth.
These are comfortable dimensions for Dr. Ahmed Zewail, holder of the Linus Pauling chair and professor of chemistry and physics at Cal Tech, who also won the Nobel Prize in Chemistry in 1999. Not small himself, and frankly large in enthusiasm, the Egyptian scientist presented the NIH Director's Lecture "Physical and Biological Sciences at New Limits" on May 4 in Masur Auditorium.
His audience swarmed, prompting one guest to comment before the lecture, "It's amazing that this many people would come to a talk on physics."
Maybe it was Nobel star power, or perhaps Dr. William Eaton, chief of NIDDK's Laboratory of Chemical Physics, who had invited Zewail, knows lots of closet physicists of all ages on campus. In any event, Zewail, who was making his first visit to NIH, was a popular draw.
"I am so impressed by what I've seen and I've seen only a small fraction of [the campus] " Zewail marveled, "that if I had to vote, I would triple the budget for NIH...and for NSF, too."
He joked that one published account of his Nobel prize listed him as being born in 1496, a factual error doubly offensive given the precision demanded within his field. "When I went to Stockholm (to accept the Nobel), I pointed out that I had the benefit of 500 years to complete my work."
He spent much of his talk proving that physics and biology "are like brothers and sisters." Peer deeply enough into the fundamentals of life and you find yourself in the world of atoms and the bonds linking them. Eminent physicist and fellow Nobel laureate Erwin Schrödinger wrote a book more than 50 years ago titled What Is Life? (1944), Zewail reminded the audience. "The nature of the chemical bond...is essential to biology. Three-fourths of biology, not one half, is based on it."
He pointed out that studies of atomism have been awarded four recent Nobel prizes: in 1986 for scanning tunneling microscopy, in 1989 for single electron trapping and spectroscopy, in 1997 for laser trapping and cooling, and in 1999, when Zewail earned the honor for work in laser femtochemistry.
"Change (in chemical reactions) is always hard to capture," he admitted. The current state of the art, in terms of speed, is 4 femtoseconds, he reported; his team is imaging billions of molecules at the moment, but with a fineness that is honing away at the edges of quantum uncertainty (the famed inability to say where a particular atom resides at a given moment it can only be expressed in likelihoods; Zewail had quipped, by way of summarizing Heisenberg's Uncertainty Principle, that "you cannot be both rich and beautiful at the same time"). Zewail's lab "can localize position to within one-tenth of an Angstrom, in femtospeed," he said.
He described the experiment "that is closest to my heart because it worked" using sodium iodide, a simple two-molecule system that yields nicely to the investigations of classical physics. Foreseen, as two new machines for capturing atomic minutiae are built in his lab, is progression from simple molecules to crystals, and eventually to sizes in the range of biological molecules of interest.
Dr. Michael Gottesman, NIH deputy director for intramural research, asked how far we are from being able to image macromolecules including proteins. "The techniques are there," Zewail assured him. "It is only a question of more work."
Zewail, who has been at Cal Tech since 1976, thanked the many colleagues who have passed through or collaborated with his lab; they literally span the globe. Having come to NIH from Zurich, where he had participated in events honoring the 75th anniversary of Erwin Schrödinger's revolutionary papers on wave mechanics (an elaboration of quantum theory), Zewail obviously relishes world travel and wide friendships; he divulged to the audience that gourmandizing is a side benefit of his international career.
"Thank you for teaching us that small is beautiful, which we already knew at NIH, but also that fast is exciting," concluded Gottesman.
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