With ab initio theory and elastic scattering Green's function method, electronic structure, conductance and current of 1,4-phenylene diisocyanide molecule are investigated. It shows that charge of system is transferred and redistributed by electric field. Electron gathering area and dissipation area are formed near interface between molecule and electrodes. Additional electric dipoles are formed, which restrain conductance and current of molecule. Moreover, molecular orbit energy and coupling coefficients between molecule and electrodes are influenced obviously by electric field, which make differences in molecular voltage current characteristic.

With ab initio theory and elastic scatering Green's function method,current and conductance of heterocyclic molecular isomers are investigated.It shows that expending orbits and coupling coefficients have dominant influence on electronic transport of molecular systems.Positions of nitrogen atoms and terminal atoms in molecules affect expending of molecular orbits and coupling degree,which results in difference in electronic transport.

With ab initio theory and elastic scattering Green's function method,electronic transport of organic molecule 1,4-phenylene diisocyanide is investigated with two electrode configurations and coupling modes.Coupling properties,electronic transport spectrums,positions of turning-on voltage,distributions of conductance platform,and responses of current with different configurations and couplings are studied.Coupling coefficients,height of conductance platform and current can be affected by changing the distance between two electrodes.

With first principle and hybrid density functional theory,electronic structrue of an organic molecule bis-(4-mercaptophenyl)-ether is calculated.Electronic transport is studied by elastic scattering Green function method.It shows that electronic field has obvious influence on electronic structrue of molecular system.The current and conductance exhibit nonlinear changes.They are close to experimental results.