dc.creator Berry, R. Stephen en_US dc.creator Moffitt, William E. en_US dc.date.accessioned 2006-06-15T12:47:13Z dc.date.available 2006-06-15T12:47:13Z dc.date.issued 1956 en_US dc.identifier 1956-G-1 en_US dc.identifier.uri http://hdl.handle.net/1811/7485 dc.description Author Institution: Mallinckrodt Chemical Laboratory, Harvard University en_US dc.description.abstract The 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.extent 126061 bytes dc.format.mimetype image/jpeg dc.language.iso en en_US dc.publisher Ohio State University en_US dc.title THE $\Pi$-ELECTRON STRUCTURE OF BUTADIENE en_US dc.type article en_US
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