X-ray photodesorption yields of and H¹²C¹⁴N from a pure ice irradiated at 15 K as a function of the incident photon energy. The solid noisy lines are associated with the desorption yield derived from a continuous irradiation from 395 to 420 eV, whereas the squares with error bars result from the desorption measurements corresponding to irradiation at fixed energies for a few tens of seconds. The TEY measured simultaneously during the continuous irradiation are shown as dashed red lines in arbitrary units.