Anomalous molecular orbital variation upon adsorption on wide band gap insulator

摘要

It is commonly believed that organic molecules are physisorbed on the idealnon-polar surfaces of wide band gap insulators with limited variation of theelectronic properties of the adsorbate molecule. On the basis of firstprinciples calculations within density functional theory (DFT) and $GW$approximation, we show that this is not generally true. We find that themolecular frontier orbitals undergo significant changes when a hydroxy acid(here we chose gluconic acid) is adsorbed on MgSO$_4$$\cdot$H$_2$O(100) surfacedue to the complex interaction between the molecule and the insulating surface.The predicted trend of the adsorption effect on the energy gap obtained by DFTis reversed when the surface polarization effect is taken into account via themany-body corrections.