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Optical activity of saccharides—the vacuum‐uv origin of sodium‐D rotation
Author(s) -
Stevens Eugene S.,
Sathyanarayana Bangalore K.
Publication year - 1988
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.360270305
Subject(s) - chemistry , degenerate energy levels , polarizability , exciton , excitation , optical rotation , atomic physics , perturbation theory (quantum mechanics) , spectral line , molecular physics , symmetry (geometry) , rotation (mathematics) , molecule , condensed matter physics , physics , quantum mechanics , geometry , mathematics , organic chemistry
A semiempirical theory of saccharide optical activity indicates that the dominant source of Na D rotation is a vacuum‐uv CD band near 150 nm, a band observed experimentally in polysaccharide film CD spectra. The model is a modification of polarizability theory in which high‐energy electronic excitations are coupled by degenerate perturbation theory, giving rise to “molecular excitons.” The existence of an excitation mode well separated in energy from even higher energy modes arises from the local symmetry of tetrahedral carbon atoms in a puckered ring structure. Calculated Na D rotations correlate well with experimental values.