Electron affinity evaluation using anion lifetime for p-coumaric and coumarin-3-carboxylic acids

The molecules of 𝑝-coumaric and coumarin-3-carboxylic acids were studied by the method of mass spectrometry of negative ions of resonant electron attachment. The average lifetime of negative molecular ions relative to spontaneous electron emission has been experimentally measured. With Arrhenius approximation, the value of the adiabatic electron affinity (𝐸𝐴𝑎) was estimated. It is established that the theoretical values of EAa calculated by the B3LYP/6-31+G(d) method with minimal addition of diffuse functions as the difference of the total energies of the neutral molecule and the radical anion correlate well with the values of EAa obtained from the experiment.