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Re: "SCF IS UNCONVERGED, TERMINATED NORMALLY"

Thomas Pijper
thomaspijper@hotmail.com

Dear Pejer,

This behavior is normal. The maximum number of SCF iterations can be set with the MAXIT keyword of the \$CONTRL group. Its default value is 30, meaning that the SCF program will be aborted after 30 iterations, after which eigenvectors and such will be printed as normal. This is what happened in your case.

"Terminated normally" simply indicates that Firefly did not abort due to a program error.

In order to achieve convergence with your system I recommend you first try increasing the value of MAXIT. If the number of iterations required turns out to be large, you can play with settings in the \$SCF group and/or choose a different initial guess. Finally, you may want to recheck your geometry -- many convergence problems can be traced back to a unphysical input geometry.

Kind regards,
Thom

On Sat Jun 7 '14 3:36pm, pejer wrote
------------------------------------
>Dear Firefly user,
>I was trying to perform ROHF calculation with diffuse function and INTTYP=pople, here is the short version of the input.

>SCFTYP=ROHF, INTTYP=POPLE, GBASIS=N31 NGAUSS=6 NDFUNC=1 NPFUNC=1 DIFFSP=.T.

>the output file was written something like this:
>                                                                                                           NONZERO    BLOCKS
> ITER EX   TOTAL ENERGY      E CHANGE  DENSITY CHANGE    DIIS ERROR      VIR. SHIFT       DAMPING        INTEGRALS   SKIPPED
>          * * *   INITIATING DIIS PROCEDURE   * * *
>   1  0 -2115.850844955 -2115.850844955**************   0.339340691     0.000000000     1.000000000             -1        -1
>   2  1 -2091.073013941    24.777831014**************   0.106404978    12.935170593     1.000000000             -1        -1
>...
>  30 29 -2095.277689998     0.954522423**************   0.142217349    11.252264981     1.000000000             -1        -1

> SCF IS UNCONVERGED, TOO MANY ITERATIONS

>......

> FINAL ENERGY IS        0.0000000000 AFTER  30 ITERATIONS
>
>
>          --------------------
>          SPIN SZ   =    0.000
>          S-SQUARED =    0.000
>          --------------------

>          ------------
>          EIGENVECTORS
>          ------------

>                      1          2          3          4          5
>                  -15.5064   -15.6178   -15.5769   -15.6042   -15.3644
>                     A          A          A          A          A

>......

>    19417527 WORDS OF    DYNAMIC MEMORY USED
>    32308798 BYTES OF    HEAP MEMORY    USED,      125655 BYTES REMAIN IN USE
> EXECUTION OF FIREFLY TERMINATED NORMALLY 11:08:42  3-JUN-2014

>but, it claimed by the last line that the calculation was performed normally.
>I want to know why it was "terminated normally" with unconverged scf?
>
>
>Best regards,

Sat Jun 7 '14 6:48pm