Phenomenological models for matrix‐assisted laser desorption ion yields near the threshold fluence

Phenomenological models were proposed to explain the experimentally observed dependence of protein ion yields with laser fluence in matrix‐assisted laser desorption. Assuming that the illuminating laser had a Gaussian intensity profile at the sample being examined, it was possible to fit the experimental points with a model that only assumes a fluence threshold for ion production. No additional dependence of protein ion yield on illuminating fluence above the threshold value was necessary to explain the data.