Low-frequency mode activity of heme: femtosecond coherence spectroscopy of iron porphine halides and nitrophorin.

ABSTRACT: The low-frequency mode activity of metalloporphyrins has been studied for iron porphine-halides (Fe(P)(X), X = Cl, Br) and nitrophorin 4 (NP4) using femtosecond coherence spectroscopy (FCS) in combination with polarized resonance Raman spectroscopy and density functional theory (DFT). It is confirmed that the mode symmetry selection rules for FCS are the same as for Raman scattering and that both Franck-Condon and Jahn-Teller mode activities are observed for Fe(P)(X) under Soret resonance conditions. The DFT-calculated low-frequency (20-400 cm (-1)) modes, and their frequency shifts upon halide substitution, are in good agreement with experimental Raman and coherence data, so that mode assignments can be made. The doming mode is located at approximately 80 cm (-1) for Fe(P)(Cl) and at appr

SUBMITTER: Kubo M 

PROVIDER: S-EPMC2765994 | biostudies-literature | 2008 Jul

REPOSITORIES: biostudies-literature