Knowledge Bank

Vibrational predissociation spectra of isotopomers of methanol dimer have been recorded in the $CO2$ laser region. Using the beam depletion method, we have observed vibrational transitions at 1028.6 and $1053.6cm-1$ for $(CH3OD)2$ with Lorentzian linewidths of 4.8 and $2.1cm-1$, respectively. These transitions are blue shifted from the fully protonated dimer by 2.3 and $1.3cm-1$ respectively. Spectra were also measured for the mixed dimer $(CH3OH)(CH3OD)$. Preliminary analysis shows that this spectrum can be described by equal contributions of the bonded and nonbonded C---O stretch for both the deuterated and protonated methanol subunits. This suggests that there is no preference of the deuterated subunit to occupy the donor or acceptor position in the mixed dimer.