Diffusion monte carlo study of the hydrogen molecules adsorbed on C4H3Li

Diffusion Monte Carlo (DMC) simulations were used to calculate the binding energies for hydrogen molecules adsorbed on the lithium metal–organic complex C4H3Li. The calculations use all-electron DMC techniques where every electron is explicitly included in the simulation. Also we have systematically studied it using density functional theory (DFT) methods, revealing that each C4H3Li can hold up to four H2 molecules and the adsorption distance is about 2.2 A. The DMC binding energies are in the range of 0.055–0.143 eV and are compared with those obtained with DFT using various exchange-correlation functionals, with values ranging from 0.029 to 0.504 eV. These results indicate that caution is required applying DFT methods to weakly bound systems such as hydrogen storage materials based on lithium-doped metal–organic frameworks. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011