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Re^3: Error: GRADIENT IS AVAILABLE ONLY FOR RHF MP2 RUNS

Thomas Pijper
thomaspijper@hotmail.com


Dear Leira,

You could use a different method, such as UDFT or CASSCF. UMP2 is difficult -- as there is no way to calculate UMP2 gradients in 7.1.G, the only possibility is to use the TRUDGE method, which can only be used for small molecules and which isn't very straightforward in its use. TRUDGE is documented in the current manual; see pages 150 and 183-184. Keywords can be found in the older Firefly_input_rev002.pdf manual. In addition, some input examples using TRUDGE are available.


Kind regards,
Thom


On Mon Nov 25 '13 7:30am, Leira Ruth A. F. wrote
------------------------------------------------
>Dear Thom,

>Thanks for your reply.

>Does it mean that there's no way we can optimize geometry for radicals in Firefly 7.1.G?

>Sincerely,
>Leira

>On Thu Nov 21 '13 11:09am, Thomas Pijper wrote
>----------------------------------------------
>>Dear Leira,

>>Analytical gradients are available only for RHF wavefunctions. This is the case for both Firefly 7.1.G and Firefly 8.0.0. However, Firefly 8.0.0 is able to calculate gradients numerically, so you could use this to perform a geometry optimization with your system.

>>MP2 and numerical gradients are described fully in the manual.
>>
>>
>>Kind regards,
>>Thom
>>
>>
>>
>>On Thu Nov 21 '13 7:19am, Leira Ruth A. F. wrote
>>------------------------------------------------
>>>Dear colleagues,

>>>I made an mp2 optimization run with scftyp=uhf for a methyl radical. However, I get this message -  GRADIENT IS AVAILABLE ONLY FOR RHF MP2 RUNS then the calculation terminates. Does anyone know why this happens? I'm using Firefly 7.1.G in a desktop computer.

>>>Below is my input file and attached is the output file.

>>>#NAME: Leira Ruth A. Fulgueras
>>>#open shell optimization for CH3
>>> $CONTRL ICHARG=0 MULT=2 RUNTYP=Optimize SCFTYP=UHF
>>>    EXETYP=CHECK MPLEVL=2 COORD=cart MAXIT=100
>>>    DFTTYP=None ECP=None INTTYP=POPLE LOCAL=NONE
>>>    MOLPLT=.T. PLTORB=.T. AIMPAC=.F. NOSYM=0
>>> $END
>>> $SYSTEM TIMLIM=600 MEMORY=1000000 $END
>>> $BASIS  GBASIS=N31 NGAUSS=6 NDFUNC=1 NPFUNC=0
>>>         NFFUNC=0 DIFFSP=.F. DIFFS=.F.
>>> $END
>>> $SCF DAMP=.false. DEM=.false. DIIS=.false. DIRSCF=.true.
>>>    EXTRAP=.true. RSTRCT=.false. SHIFT=.false. SOSCF=.true.
>>> $END
>>> $CUBE   CUBE=.T. MESH=COARSE
>>> $END
>>> $STATPT METHOD=GDIIS NSTEP=200 hssend=.t. nprt=-2 PURIFY=.t.
>>> $END
>>> $FORCE TEMP=298.15
>>> $END
>>> $GUESS GUESS=HUCKEL
>>> $END
>>> $DATA
>>>CH3
>>>C1
>>>C  6.000000 -0.000004 0.000004 -0.000125
>>>H  1.000000 -0.775777 -0.740656 0.000626
>>>H  1.000000 1.029320 -0.301520 0.000626
>>>H  1.000000 -0.253533 1.042166 0.000626
>>> $END
>>>


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