Energy Decomposition Analysis (EDA)
We're going to build a water dimer, where an attractive interaction takes place between the hydrogen-bond donor (left) and hydrogen-bond acceptor (right).
- Construct the water dimer by first building one water molecule within the GUI
- Select All, Copy+Paste, and move the second water molecule to the right to separate them
- Set the O-O distance to hydrogen-bonding distance (ca. 2.90 Å)
- Reorient the molecules such that a hydrogen-bonding orientation is obtained (or use these coordinates)
- Choose the following setup:
- XC functional: S12g-D3 (GGA-D)
- Relativity: Scalar
- Basis set: TZ2P
- Frozen core: Small
- Numerical quality: Good
- Go to [Model]:[Regions]
- Select one molecule, and click on the [+] sign
- Select the other molecule, and click again on [+]
- Go to [Multilevel]:[Fragments], and select [Use fragments]:[Yes]
- Save
- Run
Analysis
- Once the job has run, go to [SCM]:[Levels], to see how the molecular orbitals of the two fragments are combined into the MOs of the dimer
- Go to [SCM]:[Output] to see the output, and then go to [Properties]:[Bonding Energy Decomposition] to inspect the bonding energy (-5.5 kcal·mol-1)
Further reading
