HIGH RESOLUTION ELECTRONIC SPECTROSCOPY OF PHENOL-METHANOL

$^{a}$ G. Berden, W.L. Meerts, M. Schmitt and K. Kleinermanns. J. Chem. Phys. 104 (1996), 972.Author Institution: Heinrich-Heine-Universit\""{a}t, Institut f\""{u}r Physikalische ChemieThe rotationally resolved electronic spectrum of the hydrogen bonded $phenol(MeOH)_{1}$ cluster at $35933 cm^{-1}$ in a molecular beam is presented. The vibronic origin band consists of two sub-spectra separated by approximately 3.5 GHz, exhibiting an intensity ratio of approximately 16:9, with the weaker band shifted to higher frequencies. Both sub-spectra are ab hybrid bands with an intensity ratio of $I_{a}/I_{b} = 1/3$. As in $phenol(H_{2}O)_{1}^{a}$ the phenolic moiety acts as proton donor in this cluster system. The observed splitting into sub-bands is attributed to the methyl group internal rotation, however. This differs from $phenol(H_{2}O)_{1}$ that shows a splitting due to a torsional motion of water. From the obtained data we determine parameters of the intermolecular structure of the cluster as well as for the torsional potential of the methyl rotation