Knowledge Bank

Multimode Jahn-Teller analysis of the e modes in the $X~$ state of the $CH3O$ radical has been initiated using the SOCJT $programa$ with special attention being paid to the asymmetric C-H stretch mode $(n4)$ for which there are several relevant experimental observations. Dispersed Fluorescence (DF) spectra have been recorded via excitation of $A~2A13n41(n=1,2,3)$ combination levels for $CH3O$. DF spectra have also been obtained upon $3n(4\prime )1(n=1,2)$ LIF excitation for the $CHD2O$ isotopomer. For both isotopomers the observed spectra reveal the quartet vibronic structure in the C-H stretch mode region. The observed quartet structure exhibits a large $(\sim 130cm-1$ for $CH3O$ and $\sim 160cm-1$ for $CHD2O)$ separation; each component is further split into doublets ($\sim 25cm-1$ and $\sim 35cm-1$ respectively for $CH3O$ and $CHD2O$). In addition, the rotationally resolved structure of the $\nu 4$ C-H stretch band of $CH3O$, recorded via stimulated emission pumping technique was compared with that recently obtained from IR $spectrab$. The implications of the rovibronic structure for the vibronic assignments will be discussed.