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Re: Can not optimize geometry in MP2/aug-cc-pVDZ

Alexander Vasyanin

Hi All!

I didn't solve the problem. Looks like it appears when diffusion functions added to the basis sets: with 6-311G* and cc-pVDZ it optimizes, but 6-311+G* and aug-cc-pVDZ both failed, oscillating with GMAX not less than 1E-4.

I think the problem is with some gradient artifacts so I also tried to set tighter values to NCONV (8) in addition to values for $MP2GRD recommended by Prof. Granovsky, but it breaks SCF convergence.

So I gave up...

On Mon Feb 9 '15 7:47pm, Alexander Vasyanin wrote
>Dear All,
>I've got a problem with geometry optimization (see attached input file). DFT methods (B3LYP, PBE0) with the same input geometry converge fine, but MP2 fails to converge showing a progress like this:

>$ grep 'E=' 1.dat | cat -n
>     1  E=     -727.7926962177  GMAX=   0.0001417  GRMS=   0.0000243

>I've tried to use symmetry (CS) to make calculation faster with IHREP=5 option, but it also didn't help to reach convergence even after 40 iterations.

>Is it possible to improve convergence (may be with some option in $MP2GRD)?

>Thanks in advance!

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