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Alex Granovsky

gran@classic.chem.msu.su

Dear Thom,

Sorry for the delayed reply. Quite often, geometry optimization

of higher roots of SA-CASSCF can be the real headache.

While it is difficult to provide the 100% working recipe, I'd

recommend you the following.

First, starting with your SA-CASSCF orbitals for three lowest roots

in averaging, perform a single-point SA-CASSCF calculation with

wstate set to

WSTATE(1)=1,1,0,0,0,0,1,1

and activated state tracking. If you are lucky, SA-CASSCF will

converge to different orbitals better describing initial

seventh and eighth states. These states will be lowered by

energy and most likely the final order of states will be different.

After getting new orbitals, perform CASCI calculations and find the

states that are lower or close by energy to the states of interest.

It is usually good idea to include them into averaging as well,

especially if one is exploring different molecular geometries.

Indeed, the lack of convergence you have encountered is most

likely due to CASSCF state passing region of avoided crossing.

Hence, you need to include the states involved into this crossing

into SA-CASSCF procedure, all with equal weights. Ideally, new

averaging would include all relevant SA-CASSCF states, with orbitals

still allowing rather good description of the excited states of

interests.

Kind regards,

Alex Granovsky

On Wed Mar 23 '11 1:15am, Thomas wrote

--------------------------------------

>Dear Alex,

>For the geometry optimization of the ground state structure, I used SA-CASSCF with averaging over the three lowest CASSCF states.

>As for the follow-up XMCQDPT2 calculation, I tried to follow the guidelines on XMCQDPT2 that you've posted earlier.

http://classic.chem.msu.su/cgi-bin/ceilidh.exe/gran/gamess/forum/?C35e9ea936bHW-7650-1219+00.htm

>I started with averaging (both for CASSCF as well as for XMCQDPT2) over the five lowest states. The settings that I ended up using in order to include all contributions larger than 0.1 are as follows:

>

$MCSCF CISTEP=GUGA MAXIT=400 NTRACK=16 $END $DRT GROUP=C1 FORS=.T. NMCC=104 NDOC=5 NVAL=5 $END $GUGDIA NSTATE=18 ITERMX=400 $END $GUGDM2 WSTATE(1)=1,1,1,1,0,1,1,1,1,0,0,0,0,0,0,1 $END $XMCQDPT NSTATE=20 EDSHFT=0.02 THRGEN=1D-9 WSTATE(1)=1,1,1,0,0,1,1,1,1,0,0,0,0,0,0,1,-0 AVECOE(1)=1,1,1,0,0,1,1,1,1,0,0,0,0,0,0,1,-0 $END

>Thank you for your help.

>

>

>Kind regards,

>Thom

>

>

>

>On Tue Mar 22 '11 5:47pm, Alex Granovsky wrote

>----------------------------------------------

>>Dear Thom,

>>how many states were included into your initial averaging?

>>>

EIGENVECTORS OF THE EFFECTIVE HAMILTONIAN 1 2 3 ********************************* 1 -0.996647 0.000661 -0.014560 2 -0.046349 0.056924 0.286798 3 -0.050143 -0.079306 0.127224 4 0.006949 0.001413 0.017246 5 -0.012656 0.043812 -0.068093 6 0.001191 0.175646 -0.044638 7 -0.000448 0.932143 0.006876 8 -0.003086 0.016572 -0.929936

>>Kind regards,

>>Alex Granovsky

>>

>>

>>

>>On Fri Mar 18 '11 2:02pm, Thomas wrote

>>--------------------------------------

>>>Dear fellow Fireflyers,

>>>I'm currently studying a photochemical electrocyclization reaction, using the CASSCF and XMCQDPT methods. Geometry optimizations and a relaxed PES scan of the ground state have already successfully given me the geometries of the reactant and the product (as well as the ground state transition state), so I’m now focusing on the first and second excited states.

>>>A XMCQDPT calculation of the reactant geometry shows a big reordering of the states: the second and third XMCQDPT state are mainly formed by the seventh and eight CASSCF state.

>>>

>>>

>>>

EIGENVECTORS OF THE EFFECTIVE HAMILTONIAN 1 2 3 ********************************* 1 -0.996647 0.000661 -0.014560 2 -0.046349 0.056924 0.286798 3 -0.050143 -0.079306 0.127224 4 0.006949 0.001413 0.017246 5 -0.012656 0.043812 -0.068093 6 0.001191 0.175646 -0.044638 7 -0.000448 0.932143 0.006876 8 -0.003086 0.016572 -0.929936

>>>

>>>

>>>Consequently, I would like to investigate the PES of these roots. However, during geometry optimizations I’ve found the CASSCF convergence to be very problematic. There is a lot of reordering of states and after a 2-3 optimization steps the SCF will not converge anymore. These are the keywords that I use:

>>>

>>>

>>>

$CONTRL SCFTYP=MCSCF RUNTYP=OPTIMIZE INTTYP=HONDO UNITS=ANGS FSTINT=.T. GENCON=.T. $END $SYSTEM TIMLIM=10000 MWORDS=100 $END $SMP CALL64=.T. $END $P2P P2P=.T. DLB=.T. $END $BASIS GBASIS=N21 NGAUSS=3 $END $MCSCF CISTEP=GUGA MAXIT=400 ISTATE=3 NTRACK=10 $END $DRT GROUP=C1 FORS=.T. NMCC=104 NDOC=5 NVAL=5 $END $GUGDIA NSTATE=11 ITERMX=400 $END $GUGDM2 WSTATE(1)=1,1,0,0,0,0,1,1 $END $STATPT METHOD=GDIIS OPTTOL=0.00004 NSTEP=500 HESS=GUESS NPRT=-2 HSSEND=.F. $end $GUESS GUESS=MOREAD NORB=114 $END ! Speeding up the calculation $TRANS MPTRAN=2 DIRTRF=.T. AOINTS=DIST ALTPAR=.T. MODE=112 $end ! Extra accuracy $CONTRL icut=11 $END $moorth nostf=1 nozero=1 syms=1 symden=1 symvec=1 $END $GUGDIA cvgtol=1d-7 $END $trans cuttrf=1d-13 $END $mcscf acurcy=1d-7 ENGTOL=1.0d-12 $END

>>>

>>>

>>>My question is if anyone has any suggestions for achieving better convergence on higher CASSCF states.

>>>Thanks in advance!

>>>

>>>

>>>Kind regards,

>>>Thom

>>>

Mon Mar 28 '11 3:08am

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