Knowledge Bank

The far-infrared spectra of tetrahydrofuran-3-one show ring-bending ($100-120cm-1$), ring-twisting ($227-237cm-1$) difference ($115-137cm-1$), sum ($320-350cm-1$)and overtone ($200-225cm-1$) bands. A two-dimensional potential energy surface for the twisting and bending was determined and this has corresponding to twisted conformations. A potential energy surface for the $S1(n,\pi \ast$) excited state, based on previous fluorescence excitation data, was also calculated.