Absorption

[bfazi]

Hi,

I want to calculate binding energy of CO2 on CNT. Do I define CNT as a bulk configuration or a molecule configuration?

Many thanks

[Umberto Martinez]

Bulk configuration. Just check that you have enough vacuum around your CNT.

[zh]

The positive value you obtained may indicate that the interaction between CO2 and CNT is too weak. One thing should be reminded that the LDA/GGA may be not sufficient to describe the adsorption of CO2 on CNT. The correction of van der Waals force needs to be taken into account.

[Umberto Martinez]

check, Grimme DFT-D2 and the BSSE counterpoise correction
http://www.quantumwise.com/documents/tutorials/latest/Grimme/index.html/