Dear Friends,
I have optimzed a chalcone derivative using DFT/B3LYP method using different basis sets. The structural parameters of the optimized geometry show large deviation from the XRD values. Experimentally, the molecule is not planar, but theoretical results shows the planarity of the structure. How can I resolve this problem? Please help me.
Regards
Dr. Renjith
Dr Renjith,
Your DFT structures were either optimized in a vacuum or, if you chose to have it do so, in a solvent. When molecules pack in the solid state there are definite intermolecular interactions that play a role. Exactly how much is the deviation from planarity. If the potential surface is soft enough, the crystal may pack better and be overall lower in energy with a deviation from planarity.
Dear Joseph S Merola,
some important structural parameters of the molecule is attached. Deviation is more for torsional angles. Is there any problem in publishing these results? If so how can we explain this much differences.
Renjith,
Would it be possible for you to upload the .cif file from the crystal structure. That will allow me to see what kinds of interactions are affecting the dihedral angles. From my look at the table you provided, it isn't clear how significant those differences are, though in most cases they appear quite small.
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