Gold layers in central region

[jalmeida]

Hello  ,

I work with molecular junctions using gold electrodes and I would like to know more about the increasing of gold layers in the central region for reability of optimized geometry and transmission function. What is the best approach:

1. Include gold layers in the electrode extension?
2. Include gold layers in the most inner part of central region (inside of "dashed lines")?

I believe if we do not optimize the junction the results will be the same. However, if we optimize, since the electrodes extension remains not relaxed, not gold layers enough in the most inner part could gives a geometry far from the reality. What is the case?

[Anders Blom]

There is no point to make the electrode extension longer than necessary to capture all interactions. That is, once it's long enough that no terms are truncated, making it even longer will have no effect. So make sure the extension is good, then add any additional layers to the central region.

[jalmeida]

Thank you for your replay.  Maybe my question was not clear. I would like to know what is the best approach in the case the gold layers is not enough, i.e., what is the difference between including gold layers in electrode extension OR in the most inner part?