Fig. 2

Three of a series of 106 VEEL spectra acquired from a MgH₂ particle. a At the beginning of the electron beam exposure, b After 39 s, and c after 160 s of continious irradiation. The MgH₂ plasmon at 14.1 eV decreases, while the Mg plasmon at 10.1 eV arises. After roughly 3 min, all hydrogen has left the specimen. The fitted Lorentz functions describing the respective plasmon contributions are overlaid on the experimental data. The adjusted coefficients of determination, \(\bar{R}^2\), describing the goodness of the fits are 0.99, 0.97 and 0.98 in a–c, respectively. The used current density is 818 e⁻/nm²/s at an accelerating voltage of 300 kV