Ring-Puckering Motion of 2,5-Dihydrofuran

Abstract
The far infrared absorption spectrum of 2,5‐dihydrofuran was measured in the 500–50‐cm−1 region. A successive series in the spectrum was observed. The analysis of the series leads to the following ring‐puckering potential as a function of the ring‐puckering coordinate Z: V(Z)=1.557×104Z2+1.152×106Z4 (V in cm−1, Z in angstroms). No potential hump is found in this molecule. The origin of the potential and the treatment of higher‐order terms in the kinetic energy are discussed.