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

Thomas Pijper
thomaspijper@hotmail.com


Dear Alexander,

With the aug-cc-pVDZ basis one should enable spherical functions. These are enabled with

$CONTRL D5=.T. $END

See pages 68-69 of the manual for more details. Enabling spherical functions may reduce partial linear dependence in your basis and help in getting more accurate MP2 gradients.

Hope this helps.


Kind regards,
Thom







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
>     2  E=     -727.7926962929  GMAX=   0.0001120  GRMS=   0.0000170
>     3  E=     -727.7926963478  GMAX=   0.0001410  GRMS=   0.0000230
>     4  E=     -727.7926963300  GMAX=   0.0001064  GRMS=   0.0000191
>     5  E=     -727.7926963359  GMAX=   0.0000947  GRMS=   0.0000164
>     6  E=     -727.7926963183  GMAX=   0.0000374  GRMS=   0.0000059
>     7  E=     -727.7926963183  GMAX=   0.0000374  GRMS=   0.0000059
>     8  E=     -727.7926963427  GMAX=   0.0000564  GRMS=   0.0000109
>     9  E=     -727.7926821007  GMAX=   0.0022164  GRMS=   0.0003298
>    10  E=     -727.7926963076  GMAX=   0.0001419  GRMS=   0.0000216
>    11  E=     -727.7926963186  GMAX=   0.0000727  GRMS=   0.0000111
>    12  E=     -727.7926963017  GMAX=   0.0001004  GRMS=   0.0000204
>    13  E=     -727.7926963017  GMAX=   0.0001004  GRMS=   0.0000204
>    14  E=     -727.7926963256  GMAX=   0.0000705  GRMS=   0.0000113
>    15  E=     -727.7926963045  GMAX=   0.0001233  GRMS=   0.0000208
>    16  E=     -727.7926963005  GMAX=   0.0000897  GRMS=   0.0000190
>    17  E=     -727.7926963306  GMAX=   0.0001289  GRMS=   0.0000226
>    18  E=     -727.7926963143  GMAX=   0.0000295  GRMS=   0.0000066
>    19  E=     -727.7926963143  GMAX=   0.0000295  GRMS=   0.0000066
>    20  E=     -727.7926963311  GMAX=   0.0000623  GRMS=   0.0000102
>    21  E=     -727.7926960335  GMAX=   0.0002230  GRMS=   0.0000479
>    22  E=     -727.7926963305  GMAX=   0.0000966  GRMS=   0.0000163
>    23  E=     -727.7926963281  GMAX=   0.0000657  GRMS=   0.0000119
>    24  E=     -727.7926963216  GMAX=   0.0001480  GRMS=   0.0000286
>    25  E=     -727.7926963216  GMAX=   0.0001480  GRMS=   0.0000286
>    26  E=     -727.7926963217  GMAX=   0.0000691  GRMS=   0.0000123
>    27  E=     -727.7926963181  GMAX=   0.0000618  GRMS=   0.0000099
>    28  E=     -727.7926961166  GMAX=   0.0001413  GRMS=   0.0000266
>    29  E=     -727.7926962196  GMAX=   0.0000940  GRMS=   0.0000245
>    30  E=     -727.7926963158  GMAX=   0.0000997  GRMS=   0.0000160
>    31  E=     -727.7926963158  GMAX=   0.0000997  GRMS=   0.0000160
>    32  E=     -727.7926963209  GMAX=   0.0001290  GRMS=   0.0000192
>    33  E=     -727.7926963169  GMAX=   0.0000520  GRMS=   0.0000103
>    34  E=     -727.7926963562  GMAX=   0.0001067  GRMS=   0.0000186
>    35  E=     -727.7926963414  GMAX=   0.0000815  GRMS=   0.0000132

>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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