A novel type of surface vibrational sum-frequency generation spectroscopy is presented that enables a highly specific measurement of the coupling of molecules on surfaces. With this doubly vibrationally resonant technique, two-dimensional vibrational spectroscopy of molecules on surfaces becomes possible. The technique is demonstrated for the C-O stretch vibration of CO on a ruthenium (001) sur...

In recent years, negative ion photoelectron spectroscopy (PES) has emerged as a versatile technique well-suited to the study of a variety of exotic chemical species. These species include reactive free radicals [ 11, size-selected clusters [ 2 1, and the unstable collision complexes formed in chemical reactions [ 31. In a typical experiment, a mass-selected negative ion beam is photodetached wi...

Lactate dehydrogenase (LDH) catalyzes the interconversion of pyruvate and lactate. Recent isotope-edited IR spectroscopy suggests that conformational heterogeneity exists within the Michaelis complex of LDH, and this heterogeneity affects the propensity toward the on-enzyme chemical step for each Michaelis substate. By combining molecular dynamics simulations with Markov and hidden Markov model...

High-resolution gas-phase infrared spectroscopy of buckminsterfullerene (C 60 ) was attempted near 8.5 μmusing cavity ring-down spectroscopy. Solid C 60 was heated in a high-temperature (∼950K) oven and cooled using an argon supersonic expansion generated from a 12.7mm × 150 μm slit.The expected S/N ratio is ∼140 for vibrationally cold C 60 , but no absorption signal has been observed, presumab...

Quantum dynamical simulations of vibrational spectroscopy have been carried out for glycine dipeptide (CH(3)-CO-NH-CH(2)-CO-NH-CH(3)). Conformational structure and dynamics are modeled in terms of the two Ramachandran dihedral angles of the molecular backbone. Potential energy surfaces and harmonic frequencies are obtained from electronic structure calculations at the density functional theory ...

Intermolecular electronic coupling dictates the optical properties of molecular aggregate systems. Of particular interest are photosynthetic pigment-protein complexes that absorb sunlight then efficiently direct energy toward the photosynthetic reaction center. Two-dimensional (2D) ultrafast spectroscopy has been used widely in the infrared (IR) and increasingly in the visible to probe excitoni...