FIRST EXCITED STATES OF THE METHYL RADICAL

A priori quantum mechanical calculations have been carried out on the lowest $^{2}E$ state of $CH_{3}$. For pyramidal geometry the lowest energy Self Consistent Field wavefunction for $^{2}E$ is $1a^{2}2a^{2}3a^{2}1e^{3}$, while for planar geometry the lowest electron configuration is $1a^{2} 2a^{2} 1e^{4} 2e$ where the 2e orbital is diffuse. Configuration interaction calculations (1342 configurations) were carried out to investigate the mixing of these two configurations in the true $^{2}E$ wavefunction as a function of inversion angle. This work was performed under the auspices of the U.S. Atomic Energy Commission.