Simulation of Two-Dimensional Infrared Spectroscopy of Peptides Using Localized Normal Modes.

摘要: Nonlinear two-dimensional infrared spectroscopy (2DIR) is most commonly simulated within the framework of exciton method. The key parameters for these calculations include frequency oscillators their molecular environments and coupling constants that describe strength between oscillators. It shown quantities can be obtained directly from harmonic by exploiting a procedure localizes normal modes. This approach demonstrated using amide I modes polypeptides. For linear cyclic diamides hexapeptide Z-Aib-l-Leu-(Aib)2-Gly-Aib-OtBu, computed are compared with those existing schemes, resulting 2DIR spectra consistent experimental observations. incorporation conformational averaging structures dynamics simulations discussed, hybrid scheme wherein Hamiltonian matrix quantum chemical local-mode combined fluctuati...