|
|
 
|
|
 |
One midsummer’s night not too long ago, the reality of research in molecular physics came into sharp focus for Laurie Sibbach.
Sibbach, taking part in the Research Experiences for Undergraduates (REU) program run by Lehigh’s physics department, was conducting experiments with the sodium-potassium (NaK) molecule.
 She had spent a long day trying to coax two state-of-the-art lasers to operate at a particular wavelength, or frequency.
The lasers that Sibbach uses are actively-stabilized, single-frequency tunable dye and titanium-sapphire lasers. They are notoriously temperamental, because their wavelength or frequency must be controlled to one part in a billion and because they must be able to change wavelength smoothly and with extraordinary precision.
Before researchers like Sibbach can begin taking data, they must often spend hours carefully aligning the optical elements that make up the laser cavity and adjusting the electronic circuits that guarantee the required stability and control.
When a laser is being used at the extreme limits of its wavelength tuning range, achieving stable operation at an exact wavelength can be extremely difficult.
Once preparations are completed, data can be collected. But for molecular physicists, who study how molecules interact with each other and with light, this process can be even more painstaking than setting up the equipment. It can take months to measure the large number of spectral lines that yield clues about the energy levels associated with the motion of the electrons in the molecule and with the vibration and rotation of the atoms in the molecule.
Near the end of last summer, Sibbach had obtained most of the data she needed. But she wanted one final set that required the dye laser to operate at an extremely difficult wavelength near the edge of its tuning curve.
At 4:30 p.m. one day, still unable to hone in on the required wavelength, she decided to call it a day.
Then at 8 p.m., John Huennekens, professor of physics and Sibbach’s adviser, phoned Sibbach at home with the news that after three more hours of tinkering, he had gotten the laser to operate at the necessary wavelength.
Sibbach knew the first rule for researchers who use lasers: "If your equipment is working, take advantage of it." If you turn everything off and go home for the night, you may find yourself starting from scratch in the morning.
So she returned to the lab and stayed till 4:30 a.m. recording data that would eventually help her map out an interesting "double well" state of the NaK molecule.
That data and its analysis will eventually be submitted for publication, most likely in the Journal of Chemical Physics, which published a previous article describing Sibbach’s work on another state of NaK.
Sibbach’s accomplishment – authorship of an article published in a major journal – was an impressive one for an undergraduate student.
But Sibbach, who earned a B.S. in physics from Moravian College and is now pursuing a Ph.D. in physics at Lehigh, soon outdid herself. Recently, she was named one of seven finalists for the LeRoy Apker Award, the most prestigious research award given to undergraduate students by the American Physical Society (APS). As a finalist, she won a $2,000 cash award and an all-expense-paid trip to Washington, D.C., where she presented the results of her research to a panel of APS judges.
This honor was based on a 250-page paper that Sibbach wrote on NaK for her honors thesis at Moravian. She did her thesis research at Lehigh as an REU student during the summers of 1999 and 2000, and as a researcher during the last school year and summer.
Lehigh physics professors described Sibbach’s thesis as "daunting" and said it approached the level of work required for a Ph.D. dissertation.
Huennekens said simply, "Laurie’s senior thesis is the most impressive presentation of undergraduate research I have ever seen."
Huennekens has interacted with several hundred students through Lehigh’s REU summer research program, which has been funded for 14 years by the National Science Foundation and Lehigh. Participants in the program are recruited from around the U.S. and are typically among the nation’s best physics majors. Several, like Sibbach, have come from Moravian College.
All the REU students are talented and work hard during the 10-week summer program, says Huennekens.
"Laurie managed to stretch her summer research experience into almost 15 weeks; from the first day after her last final in May until the last day before classes started in the fall. She’s smart, she’s well-organized and she doesn’t give up – she keeps going as long as it takes to get the job done. She has a tremendous work ethic."
Sibbach and six other finalists for the APS Apker Award gave their presentations at the Radisson Barcello Hotel in Washington on Sept. 10. Sibbach also made time to visit Washington’s National Zoo and see the panda exhibit.
Sibbach had previously presented a poster on her research at a conference of the APS Division of Atomic, Molecular and Optical Physics in Connecticut. She was a bit nervous when she started her 20-minute talk before the Apker committee, she says, but quickly overcame her anxiety.
Today, as a Ph.D. student supported by a dean’s fellowship from Lehigh’s College of Arts and Sciences, Sibbach attends class, does homework and reads up on her field. Except for summer research projects, she will spend the next two years doing coursework.
"I really miss being in the lab," she says, "and I can’t wait for summer."
--Kurt Pfitzer
kap4@lehigh.edu
|
|
