Re: CCL:MP2/6-311G** in G92

[hommes.,at,.derioc1.organik.uni-erlangen.de (Nico van Eikema Hommes)]

      Hi Savant,
 >We are running an MP2/6-311G** calculation on a molecule C7H12 on an SGI
 >Indigo**2 machine using Gaussian92.
 >We have 190Meg swap space and 500Meg scratch space. Even when we use the
 Stingy
 >or the VeryStingy mode we still run out of scratch space. The MaxDisk is set
 at
 >400Meg and we are using the SCF=Direct.
 I fear that this system is too large for your machine. My experience with
 MP2 frequencies is that they use excessively large amounts of disk space.
 "Stingy" reduces the requirements only to some extent.
 I recently ran a MP2 freq. job with 135 basis functions, which required
 almost 2 Gb of scratch space (with the "stingy" keyword). Since yours
 is
 a 198 bf system, you'll probably need a multiple of that.
 A suggestion: look at what the sophisticated DFT methods tell you (use
 BLYP or Becke3LYP or Becke3P86). The results are often very similar to
 MP2 results.
 Best wishes,
             Nico van Eikema Hommes
 --
   Dr. N.J.R. van Eikema Hommes     Computer-Chemie-Centrum
   hommes.,at,.ccc.uni-erlangen.de       Universitaet Erlangen-Nuernberg
   Phone:    +49-(0)9131-856532     Naegelsbachstr. 25
   FAX:      +49-(0)9131-856566     D-91052 Erlangen, Germany