From owner-chemistry@ccl.net Mon Jul 22 22:11:00 2013 From: "Gabriela Arias gabriela.ariasdelarosa ~~ gmail.com" To: CCL Subject: CCL:G: What settings should I use in G09W to prevent the breaking of a bond? Message-Id: <-48989-130722200229-15322-vueSy5omOMm+kxWkDuz6Wg.:.server.ccl.net> X-Original-From: "Gabriela Arias" Date: Mon, 22 Jul 2013 20:02:28 -0400 Sent to CCL by: "Gabriela Arias" [gabriela.ariasdelarosa[-]gmail.com] Hello everyone: I am doing an optimization and frequency calculation in Gaussian09 to obtain the Raman and Infrared spectra of cysteine. In the output, the bond between the thiol group and the adjacent carbon is broken, which is wrong. What can I do to prevent this bond from breaking? These are the settings that I am using: %nprocshared=2 # opt=tight freq=raman b3lyp/6-311+g geom=connectivity Title Card Required -1 1 C -2.18907515 2.08528252 -2.35362466 C -2.51526953 1.22134909 -1.12122202 O -2.82257852 1.77040643 -0.03142030 N -0.74900832 2.37936285 -2.37861038 H -0.23470752 1.52307575 -2.42622442 H -0.53719378 2.94035858 -3.17887183 O -2.46894955 -0.20480359 -1.21525919 C -2.57949898 1.32244966 -3.63317742 H -2.02919712 0.40622247 -3.68412445 H -2.35285743 1.92271509 -4.48945717 H -2.73937700 3.00150971 -2.30267762 C -4.08814042 1.01436550 -3.60700190 H -4.35940892 0.48434527 -4.49604181 H -4.63844227 1.93059270 -3.55605487 S -4.46517029 0.01579310 -2.18253651 H -5.74849515 -0.24627848 -2.16027033 1 2 1.0 4 1.0 8 1.0 11 1.0 2 3 2.0 7 1.0 3 4 5 1.0 6 1.0 5 6 7 8 9 1.0 10 1.0 12 1.0 9 10 11 12 13 1.0 14 1.0 15 1.0 13 Best regards and thanks for your help, Gabriela