The Absorption Spectrum of Cyclopropane in the Vacuum Ultraviolet. Note on the Absorption Spectrum of Methyl Cyclopropane

Abstract

The spectrum of cyclopropane has been investigated from 600A to 2200A with high dispersion. Three very broad electronic transitions with apparent maxima at 1594, 1449, and 1202A were found. A strong continuous absorption begins at 1123A, and no resolved transitions could be observed at shorter wavelengths. A very weak band system consisting of twelve bands was found between 1889 and 1816A. It is concluded that the electronic transitions arise from excitation of an electron from a bonding molecular orbital localized principally in the carbon ring. The weak transition is interpreted as a forbidden transition. A tentative analysis of the bands in this transition is given. A note on the absorption spectrum of methyl cyclopropane is included.