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Re^5: Memory for CASSCF(8,8)

Solntsev Pasha
solntsev@univ.kiev.ua


On Sat Nov 20 '10 1:18pm, Alex Granovsky wrote
----------------------------------------------
>Hi,

>On Thu Nov 18 '10 4:15am, Solntsev Pasha wrote
>----------------------------------------------
>>Same thing with XMCQDPT2 (CASSCF(7,7))

>Actually CASSCF(14,14)
Sorry, my fault. I didn't understand exactly this notation.


>> ********** ROUTINE MQCACI **********************************************
>>***** ERROR: MEMORY REQUEST EXCEEDS MAXIMUM.
>>  1692001415 WORDS REQUIRED    140000000 AVAILABLE.

>> EXECUTION OF FIREFLY TERMINATED ABNORMALLY AT 18:58:04 LT  17-NOV-2010

>The XMCQDPT code is very flexible so you can dramatically
>reduce memory needs using additional keywords in the $xmcqdpt
>group. Please let me know if you need some help with this.

Sure. We used TD-DFT (w/ and w/o PCM + different potentials) but we were not able to reach acceptable agreement with  experiment. So i decided to use XMCQDPT2. The main problem is active space. From TD-DFT it looks like we need 7 occupied and 6 unoccupied orbitals. But i wanted to check a little bit higher active space CAS(16,16).
Also it is not clear for me. How many NSTATE should i use in $DET?
Or situation with that parameter almost same like with active space and i need to try different number of NSTATE.



>> $MCSCF cistep=aldet  maxit=200 micit=200  $end

>Regardless on your initial question, it's very bad idea to set micit to 200.

Hm.... I thought it this is a max number of micro-iterations and i can safety increase this parameter. I will try default mode.


>> $XMCQDPT inorb=1 edshft=0.2 kstate(1)=1,1,1,1,1,1,1,1,1,1  $END

>edshft=0.2 is the really HUGE shift. The recommended value is 0.02. Note, this is ISA shift (that is similar to imaginary shift), not
>the plain denominators shift (0.2 would be OK with plain shift).

Again my fault. I saw posts about MCSCF and people used 0.02.  Sorry.


>Regards,
>Alex Granovsky
>


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