dc.creator Roebber, J. L. en_US dc.date.accessioned 2006-06-15T16:49:04Z dc.date.available 2006-06-15T16:49:04Z dc.date.issued 1969 en_US dc.identifier 1969-B-1 en_US dc.identifier.uri http://hdl.handle.net/1811/15651 dc.description Author Institution: Department of Chemistry, Northeastern University en_US dc.description.abstract The gas phase absorption spectrum of the $1780{\AA}$ band of carbon suboxide has been measured photelectrically at both $300^{\circ}K$ and $200^{\circ}K$ with a 1-m monochromator having a $1.0{\AA}$ band width. The intensity of the 14 vibrational bands in the $1780{\AA}$ transition relative to each other remains unchanged on cooling to $200^{\circ}K$. This rules out the possibility that these bands are a vibrational sequence in the very low frequency $(63 cm^{-1})$ ground state bending mode and makes their assignment as a progression in a $400 cm^{-1}$ excited state bending vibration fairly definite. The regularity of this progression as it passes over the peak of the $1780{\AA}$ band implies that the linear-linear vertical transition is forbidden. Using the Herzberg-Teller theory of vibrational induced electronic transitions and a semi-empirical self-consistent field molecular orbital treatment of excited electronic states, strengths of both the $2650{\AA}$ and $1780{\AA}$ transitions have been calculated. The $2650{\AA}$ band ($^{1}\Sigma_{u}, \ ^{1}\Delta_{u} \leftarrow^{1}\Sigma^{+}_{g}$) combines with a $\pi_{g}$ vibration $(577 cm^{-1})$ to borrow intensity from the symmetry allowed $^{1}\Pi_{u} \leftarrow ^{1}\Sigma^{+}_{g}$ transition at $1587{\AA} (f \sim 1)$. The $1780{\AA}$ band ($^{1}\Sigma^{-}_{g} \ ^{1}\Sigma^{+}_{g}, \Delta_{g} \leftarrow \Sigma^{+}_{g}$) combines with the $\pi_{u}$ vibrations (63 and $660 cm^{-1}$) to also borrow intensity from the $1587{\AA}$ band. The temperature dependence of the intensity of the $1780{\AA}$ band will be compared with that predicted by the Herzberg-Teller theory. en_US dc.format.extent 170457 bytes dc.format.mimetype image/jpeg dc.language.iso English en_US dc.publisher Ohio State University en_US dc.title THE ELECTRONIC ABSORPTION SPECTRUM OF CARBON SUBOXIDE. en_US dc.type article en_US
﻿