Centrifugal Distortion and Internal Rotation Analysis in the Ground State of Trans N-Propanol

The ground state rotational spectrum of the trans n-propanol (CH3CH2CH2OH) has been reinvestigated expanding the frequency region, with respect to a previous study, from 8 to 40 GHz. A centrifugal distortion analysis has been carried out by measuring new transitions, including μa- transitions not observed before. The potential barrier V3 to the methyl top internal rotation has been determined from fourteen transitions which were found split into doublets. V3 is 2730 ± 60 cal/mole, ∢(i, a) = 29° ± 1°, assuming Ia = 3.193 uÅ2.