From tp@elptrs7.rug.ac.be Wed Jul 10 06:24:11 1996 Received: from elptrs7.rug.ac.be for tp@elptrs7.rug.ac.be by www.ccl.net (8.7.5/950822.1) id GAA01088; Wed, 10 Jul 1996 06:06:32 -0400 (EDT) Received: by elptrs7.rug.ac.be (AIX 4.1/UCB 5.64/4.03) id AA16230; Wed, 10 Jul 1996 12:07:01 +0200 Date: Wed, 10 Jul 1996 12:07:01 +0200 (DFT) From: "Park, Tae-Yun" To: Computational Chemistry List Subject: Searching transition state with MOPAC; part2 Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Dear all, I've received a lot of helpful messages from many CCLers, concerning my earlier questions on how to get the structure of transition state of the reaction, H H H H H H | \ / | | | H-C(+) + C=C ---->(TS?)----> H-C-C-C(+) | / \ | | | H H H H H H gas-phase gas-phase methyl ethylene primary propyl carbenium ion carbenium ion Thanks a lot! I greatly appreciate all the messages concerning this problem. Most of the messages pointed out that I made a mistake to prepare the input file for SADDLE calculation; all the atom should be in the same order between reactants and product z-matrix field. I made second try with a corrected input file as follows; ************************************************************** SADDLE DENSITY GRAPH XYZ CHARGE=1 PRECISE Me--->p methylation activated complex C 0.000000 0 0.000000 0 0.000000 0 0 0 0 C 8.471619 1 0.000000 0 0.000000 0 1 0 0 C 1.325912 1 162.328125 1 0.000000 0 2 1 0 H 1.108597 1 65.592545 1 -150.347214 1 1 2 3 H 1.113968 1 120.001495 1 -151.401566 1 1 4 2 H 1.108612 1 119.996246 1 -179.367538 1 1 4 5 H 1.098282 1 122.722214 1 57.159393 1 2 3 1 H 1.098328 1 122.715210 1 179.999634 1 2 3 7 H 1.098267 1 122.715210 1 -0.316483 1 3 2 7 H 1.098206 1 122.715210 1 -179.684021 1 3 2 7 0 0.000000 0 0.000000 0 0.000000 0 0 0 0 C .000000 0 .000000 0 .000000 0 0 0 0 C 1.506600 1 .000000 0 .000000 0 1 0 0 C 1.418947 1 116.688263 1 .000000 0 2 1 0 H 1.118077 1 111.116249 1 -59.952415 1 1 2 3 H 1.119762 1 109.783371 1 -179.449097 1 1 2 3 H 1.118210 1 111.069687 1 61.123405 1 1 2 3 H 1.150598 1 110.672989 1 174.990601 1 2 1 4 H 1.150955 1 110.650314 1 64.874481 1 2 1 4 H 1.109621 1 121.247902 1 -179.729874 1 3 2 1 H 1.110257 1 121.556961 1 .300391 1 3 2 1 0 .000000 0 .000000 0 .000000 0 0 0 0 ************************************************************** This time MOPAC produced a structure of transition state which is almost the same as that of reactants, that is, there was almost no change between reactants and transition state. I've tried to refine the transition state with the key words, "TS", "SIGMA", and "NLLSQ" separately, which gives no change either. Why is the result like this? Could anyone PLEASE tell me how can I go further to obtain a reliable structure of the transition state?? Thank you VERY MUCH in advance. Sincerely, Park, TAE-YUN =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= State University of Ghent Laboratorium voor Petrochemische Techniek Krijgslaan 281, Blok S5 9000 Gent, Belgium TEL:+(32)-0(9)-264-4527 FAX:+(32)-0(9)-264-4999 e-mail: tp@elptrs7.rug.ac.be =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=