Adsorbate effect on conductance quantization in metallic nanowires

We have studied conductance quantization in metallic nanowires upon adsorption of molecules with different adsorption strengths. The conductance still changes in a step-wise fashion even in the presence of strong adsorption, and the average sharpness, length, and number of the conductance steps remain unchanged. However, the step positions deviate significantly from the integer values of the conductance quantum, 2e^2/h. While the deviation may be attributed to the scattering of the ballistic electrons by the adsorbates, evidence shows that the adsorbates also affect conductance by changing the atomic configurations of the nanowires.