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The electronic structure of parallel β‐pleated sheets in proteins: An ab initio computation including electron correlation
Author(s) -
Suhai S.
Publication year - 1991
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560400410
Subject(s) - electronic correlation , wannier function , chemistry , ab initio , electron , perturbation theory (quantum mechanics) , electronic structure , hartree–fock method , polaron , anisotropy , lattice (music) , molecular physics , atomic physics , computational chemistry , condensed matter physics , physics , quantum mechanics , organic chemistry , acoustics
The electronic structure of a 2D polyglycine network with a pleated sheet structure has been computed at the Hartree–Fock level and by including electron correlation effects within the second order of many‐body perturbation theory (electron polaron model). The influence of the size of the atomic basis set and of the extension of the virtual space has been investigated both for single‐ and many‐particle properties. Comparison with the energy of the corresponding single chains showed that interchain interactions (mainly hydrogen bonding) provide an extra stabilization for the 2D network by 7.4 and 10 kcal/mole per glycine residue at the Hartree–Fock and correlated levels, respectively. The energy dispersions are rather anisotropic for all bands whose widths are about 0.5–1 eV along the polypeptide backbones and 0.1–0.2 eV in the perpendicular direction (hydrogen bonds). The HF value of the fundamental energy gap is reduced by 4 eV to 9.2 eV for electron polarons. The wave functions and interaction integrals obtained can be used to calculate further optical and lattice vibrational properties.