The torsional potential energy function of N2O4

Abstract

The infrared spectrum of dinitrogen tetroxide, N2O4, has been measured in the region 200650 cm−1 at different resolutions and temperatures. Analysis of the sequence of weak bands near 540 cm−1 involving a combination of the v6 (NO2 rocking) and v4 (torsion) modes has been performed. As a result, the shape of the potential energy function governing internal rotation about the NN bond has been determined. In the ground vibrational state, the height of the barrier at the staggered conformation is determined to be 1900 ± 200 cm−1.