Top two rows: the temperature-programmed desorption (TPD) of ¹⁵N₂ (m/z = 30) and ¹³CO (m/z = 29). From left to right: 30 K irradiation; 50 K irradiation; 100 K irradiation. Bottom two rows: the TPD of ¹³CO (m/z = 29; top) and of ¹⁵N₂ (m/z = 30; bottom) following electron bombardment. From left to right: primary, binary, ternary. Note that, for the two primary electron bombardment experiments, y-axis is scaled by a factor of 0.1.