Experimental and Theoretical Study of Sigma-Bond Electronic Transitions in Alkanes

Publisher Website
Google Scholar
Abstract
Sigma‐bond electronic transitions in alkanes have been investigated both experimentally and theoretically. Vacuum ultraviolet spectra of a large number of alkanes have been recorded in the range 50 to 94 kK and absorption intensities as well as frequencies have been determined. The implications of vapor‐phase conformational isomerism are discussed. A qualitative interpretation of the observed spectra has been developed using independent‐systems theory in connection with a simple model in which excitations in only C–C bonds are considered. A reasonably good topological matching between theory and experiment is achieved. A quantitative theory in which C–H bond excitations are included has also been developed. With this theory parameters are derived from the spectra of methane and ethane which prove sufficient to describe the higher alkanes without recourse to ``fitting.'' The theoretical procedures used are outlined in the text and described in greater detail in an Appendix.