Open AccessTwo-dimensional infrared spectroscopy of peptides by phase-controlled femtosecond vibrational photon echoes
Author(s) -
Matthew C. Asplund,
Martin T. Zanni,
Robin M. Hochstrasser
Publication year - 2000
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.140227997
Subject(s) - femtosecond , picosecond , two dimensional infrared spectroscopy , dipeptide , molecular physics , phase (matter) , infrared spectroscopy , spectroscopy , chemistry , photon , infrared , spectral line , nuclear magnetic resonance , materials science , physics , optics , peptide , laser , quantum mechanics , organic chemistry
Two-dimensional infrared spectra of peptides are introduced that are the direct analogues of two- and three-pulse multiple quantum NMR. Phase matching and heterodyning are used to isolate the phase and amplitudes of the electric fields of vibrational photon echoes as a function of multiple pulse delays. Structural information is made available on the time scale of a few picoseconds. Line narrowed spectra of acyl-proline-NH2 and cross peaks implying the coupling between its amide-I modes are obtained, as are the phases of the various contributions to the signals. Solvent-sensitive structural differences are seen for the dipeptide. The methods show great promise to measure structure changes in biology on a wide range of time scales.