Raman spectra of terephthalic acid crystals were taken in the temperature range 5 K–300 K. The temperature dependence of the vibrational frequency of the O⋯O hydrogen bond is found to contain information on the mechanism of the proton motion along the bond (hopping and/or tunneling). Onset temperatures of both tunneling and ordering (termination of the hopping) process are determined. Triplet exciton bands observed in the high-wavenumber spectral range also exhibit the relation with proton motions between oxygen atoms. The energy spectra of molecular chains of terephthalic acid, the proton potential energy along the bond, and the probabilities of tunneling as a function of the hydrogen bond lengths are calculated.
|Number of pages||5|
|Journal||Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy|
|Publication status||Published - 5 Sep 2018|
- Hydrogen bonds
- Molecular crystals
- Proton hopping
- Proton tunneling