Comment on: MALDI ionization mechanisms investigated by comparison of isomers of dihydroxybenzoic acid.

Ionization mechanism of matrix-assisted laser desorption/ionization was recently investigated by Kirmess et al. (J. Mass Spectrom. 2016, 51, 79). The authors compared the ion yields of dihydroxybenzoic acid isomers between experimental measurements and theoretical models and claimed that the predictions of chemical and physical dynamics model are in good agreement with experimental data, but the predictions of thermal model are not. Here, we show that wrong S1-S1 energy pooling rate constants and absorption cross sections were used in the aforementioned article. In addition, we suggest the authors to list the values of many parameters used in their calculations and describe how they obtained these values because these values are completely unknown.