Can anyone help me , please?
I have selected some 2D luminescent COFs for TD-DFT studies particularly to probe the excited state hydrogen interaction based on their sensing property towards nitronexplosives and other small organic molecules. Our selected COFs show the periodic system and contain powdered XRD with fractional atomic coordinates for the unit cell, sometimes the published papers also provide the xrd details regarding reference model molecule with single crystal of different group cell and lattice parameters as compared to targeted COFs.
The initial structure is constructed in the Material Studio 7 (MS) software first with given atomic coordinates for unit cell of targeted COFs and make confirmation of packing system including group cell and lattice parameters. Then we use the Gaussian-09 software for initial geometry optimization of truncated fragment of COFs with preferred basis set and theory as well.
Now, I want to justify the structure validity for further computations..
In luminescent MOFs it can be seen that they simply compare simulated geometry with provided experimental data of single crystal from CIF data.
Can I use the same method of comparison for experimental results of the referenced molecule with the optimized geometry of COFs representative fragment?
With best wishes
We have studied single crystal and powder X-ray experiments with quantum chemical calculations in the crystal. In the Gaussian-09 software, since it is a calculation of an isolated molecule, it can handle only the structure in the gas phase exactly. Using the cluster model, if you calculate with appropriate electron correlation taken into account, it is possible to reproduce the molecular structure in the crystal to some extent. However, in order to clarify the precise crystal effect, we recommend using first-principles calculation.
No. You can't. You should never use a Gaussian calculation with the hope of fully reproducing crystalline effects. If you would like to calculate, with the highest possibly quality, properties of the crystalline phase, you should use a periodic code like CRYSTAL, Quantum Espresso, VASP, or CASTEP. Then it would be appropriate to compare your generated structures to those published, and you can have confidence in your computer results.
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