Rotational Structure of the Infrared Absorption Spectrum of Hydrogen Peroxide Vapor

The internal rotation of hydrogen peroxide molecule is treated on the assumption that the hindering potential is approximately expressed by the two-term Fourier expansion: V=(V1/2)(1+cosχ)+(V2/2)(1+cos2χ). The doublet structure of the infrared absorption spectrum is considered to be caused by the existence of a double minimum in the hindering potential. The available experimental data on the microwave spectra and on the infrared combination bands yield the result of V1=244 cm—1 (700 cal/mole) and V2=319 cm—1 (910 cal/mole). Thus it is concluded that the cis barrier (452 cm—1 or 1290 cal/mole) is definitely higher than the trans one (208 cm—1 or 590 cal/mole).