By combining time-dependent density functional theory(TDDFT)and molecular dynamics(MD)simulations,we calculate the ultraviolet absorption and circular dichroism(CD)of a cyclic dipeptide,cyclo(L-Pro-D-Tyr),in the 185-300 nm region.The absorption is dominated by the phenol chromophore of tyrosine.The CD spectrum shows both phenol and amide units transitions.A crude coherent two-dimensional ultraviolet spectrum(2DUV)calculated by neglecting the two-excitation states shows a cross-peak between two transitions of the phenol in the tyrosine side chain.Additional cross-peaks between the side chain and the backbone are observed when using a chirality-induced pulse polarization configuration.
展开▼
