From owner-chemistry@ccl.net Wed Mar 28 00:49:00 2012 From: "Senthil kumar Krishnasamy supersenthil73_-_gmail.com" To: CCL Subject: CCL: Optimization with B3lyp functional in DFT Message-Id: <-46577-120327214805-993-U7cA5+ALvnw+PwnTYsWxEA^server.ccl.net> X-Original-From: "Senthil kumar Krishnasamy" Date: Tue, 27 Mar 2012 21:48:02 -0400 Sent to CCL by: "Senthil kumar Krishnasamy" [supersenthil73^gmail.com] Dear all I had optimized the structures of Trifluoromethane sulfonyl fluride [CF3SO2F] and trifluromethane sulfonic acid [CF3SO2OH] with Hartree fock method with equilibrium bond lengths and bond angles between the atoms. But the same compounds are optimized with B3lyp functional; I get a deviation from equilibrium bond length between carbon and sulphur atoms, sulphur and fluorine atoms of 0.02 , 0.05 , and 0.08 respectively. I used the Keywords of int=ultrafine, geom. =conn, opt=vtight with B3lyp functional. I didnt get the equilibrium bond lengths for the above case. The oxidation state of sulphur atom is followed by a value of 6 for both the compounds. I done the freq calculation for the same compounds by HF method and there is no imaginary frequency. What is the key word to be used to get the equilibrium bond length between carbon & sulphur atoms and sulphur & fluorine atoms in the optimization step using B3lyp functional? I expect the possible help from all. Thanks in advance By K. Senthil kumar Faculty of Physics HIndusthan College of engg & tech Coimbatore-32