Figure 5

The barrier energy curve for the desorption of hydrogen molecule from top layer of (a) pure MgH2, (b) Al doped at top layer of MgH2 (110) structure, (c) Al doped at second layer of MgH2 (110) and (d) Al doped at third layer of MgH2 (110) structure. The inset figures are the relaxed structure corresponds to initial state (I.S.), Transition state (T.S.) and final state (F.S.). The black line connecting I.S., T.S. and F.S. are only for guide to the eye. Ea denote the activation barrier energy.