Investigation of an H-bonded dimer: Calculations of bonding structures andtemperature dependence of the librational substructure of the OH-stretching band

We demonstrate data from time-resolved spectroscopy and quantum statistical thermodynamics of ab initio calculated molecular clusters for 2,2-dimethyl -3-ethyl-3-pentanol (DMEP). The association of the molecules to dimers, onl y, is supported by the numerical investigation indicating a weak H-bond. Th is is in agreement with NMR experiments and data from conventional IR spect roscopy. From time-resolved IR spectroscopy of a 2 M DMEP sample diluted in CCl4 in the temperature range from 260 K to 343 K a librational substructu re of the proton donor OH-band is suggested from spectral holes and satelli te holes in the sample bleaching. With these spectral components we are abl e to fit the temperature dependent conventional IR-absorption spectrum of t he sample in the investigated range from 260 K up to 343 K. (C) 1999 Americ an Institute of Physics. [S0021-9606(99)02037-1].