| Abstract
| - The vibrational frequency of the amide I transition of peptides is known to be sensitive to the strength of itshydrogen bonding interactions. In an effort to account for interactions with hydrogen bonding solvents interms of electrostatics, we study the vibrational dynamics of the amide I coordinate of N-methylacetamide inprototypical polar solvents: D2O, CDCl3, and DMSO-d6. These three solvents have varying hydrogen bondingstrengths, and provide three distinct solvent environments for the amide group. The frequency−frequencycorrelation function, the orientational correlation function, and the vibrational relaxation rate of the amide Ivibration in each solvent are retrieved by using three-pulse vibrational photon echoes, two-dimensional infraredspectroscopy, and pump−probe spectroscopy. Direct comparisons are made to molecular dynamics simulations.We find good quantitative agreement between the experimentally retrieved and simulated correlation functionsover all time scales when the solute−solvent interactions are determined from the electrostatic potential betweenthe solvent and the atomic sites of the amide group.
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