Re: CCL:G:summary AM1 vs PM3

 Dear Pjotr,
 I was missing the original question and saw only the summary.
 I would like to draw your attantion to a very fundamental problem with the core
 repulsion function in PM3. It might have an unphysical minima which stabilize
 unrealistic H-H, C-H or O-H  interactions.
 Some of the consequences were  shown in the paper: J. Comp. Chem. 14 (1993) 895
 by me and it was also reported in  QCPE Bull. 11 (1991) 5.
 Be careful, because the QCPE figures contain errors.
 The reprints of J. Comp. Chem. 14 (1993) 895 are available in limited number
 from me. Meantime I have discovered lot of unpublished problems which are
 related with this CRF problem. I have to say the problem is very serious.
 If you have structures with H-H distances below 2 angstrom it will occur.
 The AM1 is free from this error.
 Gabor I. Csonka                 Budapest University of Technology
 FAX: (361) 463.36.42            Inorganic Chemistry Dept. Ch. Bldg
 csonka' at \`           H-1111, Bp. Szent Gellert ter 4