Relaxation of devices (optimize the geometry of a two-probe system)

[hendchem2024]

I am a beginner in the ATK software
I'm trying to relax the device (optimize the geometry of the two-probe system). The two-probe system is the placement of a single organic molecule between two gold electrodes.
Is it better to perform the geometric optimization on the entire two-probe system (two electrodes + the central region), or to perform the optimization only on the central region?

[AsifShah]

As a rule, you need to optimize electrodes separately first and then create the structure you want.
After that the central region should include some portion of electrodes and your molecule and then optimize all of central region.

PS: During optimization - electrode and electrode extensions will be fixed.

Thanks