Physicists develop way to identify molecules by vibrational signatures Professor Wilson Ho, center, and graduate students Mohammad Rezaei, left, and Barry Stipe show off their "homemade" scanning tunneling microscope in a basement laboratory in Clark Hall. The instrument, enclosed in a vacuum chamber and cooled by liquid helium, is precise enough to resolve parts of molecules. Frank DiMeo/University Photography By Bill Steele Ever since the invention in 1982 of the scanning tunneling microscope (STM), which can see single atoms, scientists have been trying to use the instrument to examine the bonds that hold atoms together in molecules. In a significant advance, a team of Cornell physicists has successfully made a measurement of the frequency at which atoms in a bond are vibrating against each other in a single molecule of acetylene. The research for the first time provides a way to identify single molecules by their vibrational signatures and to study how their bo...