Based on first-principles plane-wave calculations, we explored the method with the ethylene molecules and Ti, Li atoms intercalated into the graphite to open space for the physisorption of hydrogen. And our simulation indicated that the interlayer distance of the graphene is close to the optimal physisorption of hydrogen with this method. From our computation, we got that the type of 3 x 3 supercell has the lowest converge energy and is energetically favorable. The energy barrier of changing the type of 2 x 2 supercell to 3 x 3 supercell is high. (C) 2009 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.