CCL:G: Gaussian problems

 Sent to CCL by: "Robinson, James" [James.Robinson-x-evotec.com]
  Hi,
 You Gaussian input needs a blank line between title and
 charge/multipilicity. Also add a few blank lines after the input of the
 second z-matrix, this does help sometimes. If you have Molden, check
 that the atom ordering are the same and if problems persist I suggest
 you try a saddle calculation using MOPAC and use cartesian coordinates
 for the two input structures in your mopac saddle calculation.
 I cannot immediately recall how the out from NMR jobs compare to TMS.
 Some calculation often need to be compared to TMS to compare
 calculations, you may need the difference between TMS and your
 calculated molecule. I also suspect that the basis set for your NMR
 calculation maybe too small, daft I know, but perhaps 6-311+(2d,p) may
 be more adequate. Also I think the NOSYMM keyword is useful
 Hope this helps or at least causes some thought.
 Dr James J Robinson
 Evotec, Oxford.
 -----Original Message-----
 > From: owner-chemistry^^^ccl.net [mailto:owner-chemistry^^^ccl.net]
 Sent: 26 April 2006 16:42
 To: Robinson, James
 Subject: CCL:G: Gaussian problems
 Sent to CCL by: "Melanie  Trusselle" [mt237]|[bath.ac.uk] Dear All, I
 am
 a new user of Gaussian and have encountered two problems that I have
 been unable to resolve. The first problem is the calculation of the
 energy barrier between two conformers. I am using QST2 for this and my
 input is below.
 %chk=QST2.chk
 %mem=500MB
 %nproc=1
  pm3 Opt=QST2
 find barrier for chair-boat interconversion
 1 1
 zmatrix of first structure
 1 1
 zmatrix of second structure
 This input gives the error message shown below:
  Symbolic Z-matrix:
  End of file in GetChg.
  Error termination via Lnk1e in /usr/local/g03/l101.exe at Tue Apr 25
 14:53:45 2006.
  Job cpu time:  0 days  0 hours  0 minutes  2.1 seconds.
  File lengths (MBytes):  RWF=      7 Int=      0 D2E=      0 Chk=      1
 Scr=      1
 I believe it relates to a lack of memory so I have tried changing %mem
 and have specifed extra memory when submitting the job but this has not
 solved the problem. I an aware that this question has been asked
 previously, and appologies for asking it again but there is no answer
 available.
 I am also interested in obtaining the J coupling constants for a
 molecule. I have used the following commands:
  nmr=SpinSpin b3lyp/6-31g(d) geom=connectivity
 An section of the output is:
 Total nuclear spin-spin coupling J (Hz):
                 1             2             3             4
 5
       1  0.000000D+00
       2  0.482568D+02  0.000000D+00
       3  0.581831D+02  0.557526D+01  0.000000D+00
       4  0.167946D+03 -0.143914D+00 -0.160153D+01  0.000000D+00
       5  0.107532D+01  0.576884D+02 -0.428170D+00  0.621590D+01
 0.000000D+00
 This is different from what I was expecting and I do not know how to
 relate it to my NMR specra or even if I have given the correct input.
 If anyone can advise me on these matters I would be most grateful.
 Thank you in advance.
 Melanie Trusselle
 mt237#,#bath.ac.uk
 University of Bath, UKhttp://www.ccl.net/cgi-bin/ccl/send_ccl_messagehttp-:-//www.ccl.net/chemistry/sub_unsub.shtmlhttp-:-//www.ccl.net/spammers.txt