From xiaopeng@astro.ocis.temple.edu Mon Feb 5 08:55:28 1996 Received: from astro.ocis.temple.edu for xiaopeng@astro.ocis.temple.edu by www.ccl.net (8.6.10/950822.1) id IAA13039; Mon, 5 Feb 1996 08:41:37 -0500 Received: (from xiaopeng@localhost) by astro.ocis.temple.edu (8.7.1/8.7.1) id IAA07086; Mon, 5 Feb 1996 08:41:37 -0500 (EST) Date: Mon, 5 Feb 1996 08:41:37 -0500 (EST) From: Peng To: ccl Subject: Strange for G92 and spartan in optimization of dimethyleacetylene Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Dear netters, I encounter a stupid mistake..It must because I did something "stupid" wrong. could anybody kindly point out? I try to optimize the structure of din=methylacetylene, however, no matter the 2 methyle group is anti conformation or eclipse conformation..strange) I do it always turrns out the optimized structure is a saddle point(at rhf/6-31g level) one of the input file for Gis attached below and another is just cheange D4=0.0 If I use Spartan4.0 to optimize it, it also turns out a saddle point. but we know this must be a local minium Please help! Thanks in advance! %chk=butyne #RHF/sto-3g opt optcyc=100 test run the optimization of 2-butyne 0 1 C C 1 Rz X 1 1.0 2 A1 C 1 R1 3 A1 2 180.0 X 2 1.0 1 A2 3 180.0 C 2 R2 5 A2 1 D1 H 4 RH1 1 AH1 3 D2 H 4 RH2 1 AH2 7 D3 H 4 RH3 1 AH3 7 -D3 H 6 RH4 2 AH4 7 D4 H 6 RH5 2 AH5 10 D5 H 6 RH6 2 AH6 10 -D5 variables: Rz=1.18 A1=90.0 A2=90.1 R1=1.501 R2=1.5001 RH1=1.094 AH1=109.4 RH2=1.0941 AH2=109.41 RH3=1.942 AH3=109.42 RH4=1.09411 AH4=109.411 RH5=1.09412 AH5=109.412 RH6=1.09413 AH6=109.412 D1=180.0001 D2=180.0011 D3=120.0 D4=180.001243 D5=120.01 --link1-- %chk=butyne #RHF/sto-3g freq geom=checkpoint guess=read test freq calculation to confirm the local minium 0 1 --link1-- %chk=butyne #RHF/6-31g(d) fopt geom=checkpoint guess=read test further optimize at 6-31g level 0 1 --link1-- %chk=butyne #RHF/6-31g(d) freq geom=checkpoint guess=read test freq calculation to confirm the local minium 0 1 xiaopeng ======================================================= Chemistry Graduate student 215-2047149(office) 215-5357188(home) xiaopeng@astro.ocis.temple.edu ======================================================