Hello everyone,
I am trying to calculate binding energies of some aromatic compounds in ORCA. For that, I got information from literature to calculate Binding as well as Interaction Energy. So, the steps to calculate Binding Energy are as follows;
1. Optimize geometry of monomers
2. Optimize geometry of dimer
3. Subtract monomers' energy from dimer's energy.
I did follow upper steps but, I am getting zero binding energy because the sum of two monomers' energies is same as dimer's energy and I got zero difference for energy.
So, I have some queries that I want to ask you;
I have taken optimized final single point energies to calculate Binding energy so, is it ok ? or any other energy should I consider to calculate binding energy?
and I am getting zero energy difference for dimer it means I am doing something wrong. So, please help me to resolve my problem.
I am attaching here my optimized output files of monomers and dimer for your reference. Here, I consider DNA base pair GCWC as a first monomer and Nitropolyaromatic Hydrocarbon as a second monomer. Thank you in advance.
Hello friends,
I found the mistake that I was doing. Actually, I was considering energies in Hartree unit and that is why I was getting minute difference in energies but when I converted that energies into kcal mol-1 and taking differences, I got higher energy. Some important energy conversions as following;
1 Hartree = 27.2 eV
1 eV = 23.06035 kcal mol-1
Dear Sharvan,
It is correct. Take carefully right units.
One more thing. In such calculations it is often reasonable to include dispersion correction. For example, B3LYP-D3 functional and the same "B3LYP D3" keyword in ORCA
See Article Effect of the Damping Function in Dispersion Corrected Densi...
for more details.
Br,
Sergey
- Badges
- Science topic
- Similar topics
- Condensed Matter Physics
- Zero