Absorption Spectra of Aldehydes

Abstract

1. RECENT observations of the ultra-violet absorption bands in the vapours of a series of homologous aldehydes have disclosed a vibrational structure, which is very similar throughout the series, since 35 measurements have given an average separation of 1025 cm.^-1 in the spectra of the higher homologues, although this interval increases to 1053 cm.^-1 in acetaldehyde. The corresponding frequency 1187 cm.^-1 in formaldehyde has been attributed to a nuclear vibration of the excited moleculeand there can be little doubt that we are now dealing with a similar nuclear vibrationof the other aldehydes.