Electronic transitions in hydrogen bonded dimers of carboxylic acids in the vapour phase: an electron energy loss spectroscopic study

An electron energy loss spectroscopic study of the formic acid dimer has shown bands centred around 7.2, 8.5, 9.8, and 11.1 eV, of which the first and the third bands are assigned to n–π* transitions and the other two to π–π* transitions; similar transitions are found in the acetic acid dimer.