Knowledge Bank

In the rotationally resolved LIF $A~\leftarrow X~$ spectrum of the jet-cooled $d2$-methoxy radical $(CHD2O)$, combination bands of $C-O(\nu 3)$ and $C-H(\nu 1)$ stretches $1131$ and $1132$ were assigned. Analysis of vibrationally resolved Dispersed Fluorescence (DF) and rotationally resolved Stimulated Emission Pumping (SEP) spectra recorded upon excitation of these bands reinforces LIF spectral assignments and gives C-H and C-O stretch along with pseudo-Jahn-Teller active $d2$-methyl rock $(\nu 6\prime \prime ,\nu 6\prime )$ vibrational frequencies in the $X~$ state. A splitting of about $\sim 200cm-1$ for $11,3111,3211$ vibronic levels of $CHD2O$ is observed and may be due to the combination of vibronic degeneracy lifting and unquenched spin-orbit interaction. The DF spectra of $CH3O$ were recorded for excitation of $X~2A13n41(n=1,2,3)$ combination bands containing asymmetric $(\nu 4)$ stretch. $X~2E13641$ and $X~2E13741$ rovibronic levels which lie $\sim 500cm-1$ and $1500cm-1$, respectively, above the $X~2ECH3O$ barrier for dissociation $CH2O+H$ products, exhibit splitting of $\sim 120cm-1$.