The effect of alkyl substitution on ionisation potential
The first ionisation potentials of series of aliphatic aldehydes, ketones, alcohols, iodides, and ethers have been measured by photoelectron spectroscopy. the effect of alkyl substitution on ionisation potential is defined in terms of two parameters; an alkyl group substituent parameter and a homologous series parameter. The same treatment is applied to other homologous series for which photoionisation values of ionisation potential are available. The substituent parameters correlate well with Taft's σ* values.