title: Simulation of the resonance Raman spectra for 5-halogenated (F, Cl, and Br) uracils.
abstract: The resonance Raman spectra of the 5-halogenated (F, Cl, and Br) uracils are simulated via the Herzberg-Teller (HT) short-time dynamics formalism. The gradient of the S1 excited state is computed at the CAMB3LYP/aug-cc-pVTZ level of theory in the conductor-like polarizable continuum model for water (C-PCM, H2O), based on the equilibrium geometry determined using PBE0/aug-cc-pVTZ in H2O (C-PCM). The simulated resonance Raman spectra show good agreement with the experimental spectra in terms of both peak positions and intensities. The differences between the resonance Raman spectra of the three 5-halogenated uracils, caused by the effect of halogen substitution, are examined in terms of ground-state normal-mode eigenvectors and excited-state Cartesian gradients, according to the HT formalism. The differences in the normal-mode eigenvectors and excited-state Cartesian gradients between 5-fluorouracil and 5-chlorouracil are used to interpret the dissimilarity between their resonance Raman spectra. Meanwhile, the similarity between the spectra of 5-chlorouracil and 5-bromouracil is explained by the correspondence between their normal modes and excited-state gradients.
authors: Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada.
authors: Shuai
authors: S
authors: Sun
authors: Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada.
authors: Alex
authors: A
authors: Brown
mesh_terms: D001976:Bromouracil / Q000737:chemistry*; D005472:Fluorouracil / Q000737:chemistry*; D015394:Molecular Structure; D011789:Quantum Theory; D013059:Spectrum Analysis, Raman; D014498:Uracil / Q000031:analogs & derivatives* / Q000737:chemistry
chemical_list: D001976:Bromouracil; D014498:Uracil; C010889:5-chlorouracil; D005472:Fluorouracil