Watching vibrational energy flow through molecules
Home page Contact us Directions for visitors Research Projects Dana D. Dlott (Curriculum Vitae) Dana D. Dlott (personal home page) David M. Dlott (personal home page) Group Members Research Publications Research Funding Research Facilities	Using 3D vibrational spectroscopy, we can directly monitor the flow of vibrational energy through molecules with angstrom spatial resolution. In our 3D technique, we use an IR pulse to pump energy into a specific vibrational transition termed the “parent” vibration. A visible probe pulse generates an anti-Stokes Raman spectrum that shows which vibrations have been excited. The probe pulse shows the decay of the parent vibration plus excitations that have been created in “daughter” vibrations by vibrational energy transfer. In molecules or nanostructures where nearly localized vibrational excitations are present with a well defined geometry, we can watch vibrational energy move with angstrom spatial resolution. For example in the ethanol molecule, OH-CH2-CH3, we can excite the OH stretch and watch energy flow through the methylene –CH2 group and into the –CH3 group by monitoring CH stretching transitions. We have done this experiment in a series of alcohol molecules of varying lengths and thereby measured the speed of vibrational energy flowing down a chain. Reference “Watching Vibrational Energy Transfer in Liquids with Atomic Spatial Resolution”, Zhaohui Wang, Andrei Pakoulev and Dana D. Dlott, Science 296, 2201-2203 (2002). Download a presentation on watching vibrational energy flow through molecules, given at the Gordon Conference on Liquids Watching vibrational energy (pdf)	Block diagram of apparatus for 3D vibrational spectroscopy in Dlott labs Measuring vibrational energy transfer across an ethanol molecule Time dependence of parent OH stretch excitation, methylene -CH2- and methyl –CH3 stretching in normal alcohols of different chain lengths