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 a bath.ac.uk
 University of Bath, UK