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dc.creatorBerry, R. Stephenen_US
dc.creatorMoffitt, William E.en_US
dc.descriptionAuthor Institution: Mallinckrodt Chemical Laboratory, Harvard Universityen_US
dc.description.abstractThe energy levels of the $\pi$ electron systems of butadiene have been computed for six spatial configurations of the molecule; of these, three are cis and three trans. The levels were determined by the following methods; (a) Valence Bond Theory including covalent structures only; (b) Antisymmetrized Molecular Orbital Theory including self-consistent field orbitals; (c) ""full"" configuration interaction; (d) perturbation theory applied to two neighboring vinyl radicals represented by ASMO functions, and (e) the method of Atoms in Molecules as applied to (a), (b), (c) and (d) above. From these calculations, it is concluded that the method of Atoms in Molecules with full configuration interaction is the only one of the methods used which predicts quantitatively the ultraviolet spectrum of butadiene. On the basis of the calculation, the observed band at 6.0 e.v. is assigned as $^{\prime} {Ag}\longrightarrow ^{\prime}{Bu}$, corresponding essentially to the one-electron excitation ${N}\longrightarrow {V}_{1}$. (The band is predicted at 6.0 e.v.). The observed 7.2e.v. absorption is assigned as $^{\prime} {Ag}\longrightarrow ^{\prime}{Ag}$ (predicted 7.7 e.v.). This band system is attributed to ${V}_{23}^{+}$, the higher energy state of the pair ${V}_{23}$ and ${V}_{23}^{+}$, the first two excited orbital configurations which are degenerate in a simple molecular orbital treatment. Excitation to the lower $^{\prime} {Ag}$ excited state, ${V}_{23}$, is predicted to lie at 6.1 e.v., and being a forbidden transition, would be masked by the strongly allowed $^{\prime} {Ag}\longrightarrow ^{\prime}{Bu}$ transition.en_US
dc.format.extent126061 bytes
dc.publisherOhio State Universityen_US

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