From: <pc...@ba...> - 2012-02-19 01:21:45
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dear All For aromatic C-C bonds (eg in benzene) I would expect the bond lengths to be 140pm. Jmol seems to think they should be 129pm. This is what I am doing: 1. Create 6C membered ring with alternate single/double bonds using the model kit; 2. Choose 'Computation/Optimise structure' from right-click context menu; At this point the single bonds are 148pm and double bonds 134pm. 2. Select the C atoms 'select _C; 3. Execute command 'connect aromatic 1.5'; 4. Execute command 'calculate aromatic' 5. Choose 'Computation/Optimise structure' from right-click context menu. This gives a six-membered ring with bond lengths all = 129pm. This means the ring is smaller than it ought to be. Are there some settings somewhere that I can change to get the correct bond lengths? Thanks Paul |