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** Discontinuous energy curve from XMCQDPT2 results **
Panwang Zhou

pwzhou@gmail.com

Dear all,Recently, I performed a MCSCF(16,14) calculation then following a XMC-QDPT2 calculation on the constructed LIIC curve among the optimized cis-HBDI, CI and trans-HBDI structures, the obtained MCSCF curve is smooth and continuous whereas the obtained XMC-QDPT2 curve is discontinuous at the CI point (see attachment). I'm not clear why the XMC-QDPT2 curve is discontinuous and how to resolve this problem?

The following is the part of input file:

$CONTRL SCFTYP=MCSCF RUNTYP=ENERGY EXETYP=RUN MAXIT=50 ICHARG=-1

MULT=1 FSTINT=.T. GENCON=.T. INTTYP=HONDO NOSYM=1

ICUT=11 ITOL=30 WIDE=.T. MPLEVL=2 $END

$SYSTEM MWORDS=480 TIMLIM=60000.0 KDIAG=0 NOJAC=100 $END

$SYSTEM MKLNP=1 NP=12 $END

$SMP SMPPAR=.T. HTTNP=1 $END

$SCF DIRSCF=.T. FDIFF=.F. NCONV=8 $END

$P2P P2P=.T. DLB=.T. $END

$TRANS MPTRAN=2 DIRTRF=.T. AOINTS=DIST ALTPAR=.T. MODE=112 $END

$MCSCF CISTEP=ALDET FULLNR=.F. SOSCF=.T. MAXIT=100 $END

$MCSCF IFORB=.T. $END

$DET NCORE=49 NACT=14 NELS=16 NSTATE=6 WSTATE(1)=1,1 DISTCI=12 $END

$XMCQDPT NSTATE=2 EDSHFT=0.02 THRGEN=1D-12 MXBASE=90 $END

$XMCQDPT HALLOC=.T. $END

$XMCQDPT IFORB(1)=-1,1,1 WSTATE(1)=1,1,-0 AVECOE(1)=1,1,-0 $END

$BASIS GBASIS=N31 NGAUSS=6 NDFUNC=1 NPFUNC=1 DIFFSP=.TRUE. $END

$GUESS GUESS=MOREAD NORB=359 $END

$MCQFIT $END

I have tried to increas the NSTATE in XMCQDPT group, however, the required memory is larger than 480 MWORDS, thus the calculation failed.

Best Regards!

Panwang Zhou

| This message contains the 68 kb attachment
[ **LIIC_curves.zip** ] MCSCF and XMC-QDPT2 Curves |

Wed May 8 '13 11:50am

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