Hi,all:
I have calculate a molecule sandwiched between two Au electrodes.And I found the MPSH spectrum of the bare molecular do not aggree with the transmission spectrum at some place(as shown in FIG1) though some aggree.There is a transmission peak at -1eV,while no MPSH.MPSH of FIG1 is for the bare molecular without any Au atoms.As I know the transmission spectrum is for the whole system including the bulk electrode and surface atoms.So I guess the transmission peak at -1eV maybe from the surface.So I recalculate the MPSH for bare molecule and the neighouring 3 Au atoms at each side (so 6 Au atoms in all)which connect the molecule to the surface.And the MPSH is in FIG2.But this time the aggreement is yet not good.
I think if there is a peak in the transmission spectrum, there should a corresponding MPSH state for the bare molecule,for the molecule connect the left and right electrodes.(Am I right?)
So who can tell me the reasion?