[molpro-user] DF-DFT-SAPT calculation requires too much memory

[WU Yanbin]

Hi, everyone,

I'm trying to do DF-DFT-SAPT calculations. And I started with the sample
example of Ne-Ar interactions.

The calculation was ran with 8 processors.
The job required 490GB memory. If the allocated memory is smaller than
400GB, the job would be killed due to inadequate memory.

The simulation time for the job is around one hour, which is much long than
DFT-SAPT calculation of the same system (which only takes about 1 minute
with 500MB memory).
The computation resources I'm using is a distributed-memory system. And I
would like to provide more details of the clusters if necessary.

Despite the long simulation time, the simulation result is the same as the
sample output.

The input and output file are attached.

Is there any keyword I should use to reduce the memory use and simulation
time?
If I'm speculating that the density fitting code is not compiled properly,
anything I should do to verify that and how I can fix this compiling
problem?

Any hint is appreciated. Do let me know if the question is not made clear.

Thank you.

Best,
Yanbin
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!examples/near_df_sapt_acdft.com $Revision: 2009.2 $ 
memory,8000,M
gdirect; gthresh,energy=1.d-8,orbital=1.d-8,grid=1.d-8
symmetry,nosym
orient,noorient
geometry={
Ne,,0.0,0.0,0.0
Ar,,0.0,0.0,6.5}
basis={
set,orbital; default,avtz         !for orbitals
set,jkfit;   default,avtz/jkfit   !for JK integrals
set,mp2fit;  default,avtz/mp2fit  !for E2disp/E2exch-disp
set,dflhf;   default,avtz/jkfit   !for LHF
}

!=========delta(HF) contribution for higher order interaction terms====
ca=2101.2; cb=2102.2 !sapt files

!dimer
{df-hf,basis=jkfit,locorb=0}
edm=energy

!monomer A 
dummy,ar
{df-hf,basis=jkfit,locorb=0; save,$ca}
ema=energy; sapt;monomerA

!monomer B
dummy,ne
{df-hf,basis=jkfit,locorb=0; save,$cb}
emb=energy; sapt;monomerB

!interaction contributions
{sapt,SAPT_LEVEL=2;intermol,ca=$ca,cb=$cb,icpks=1,fitlevel=3
dfit,basis_coul=jkfit,basis_exch=jkfit,cfit_scf=3}

!calculate high-order terms by subtracting 1st+2nd order energies
eint_hf=(edm-ema-emb)*1000 mH
delta_hf=eint_hf-e1pol-e1ex-e2ind-e2exind

!=========DFT-SAPT at second order intermol. perturbation theory====
ca=2103.2; cb=2104.2 !sapt files; 

!shifts for asymptotic correction to xc potential
eps_homo_pbe0_ar=-0.440936      !HOMO(Ar)/PBE0 functional
eps_homo_pbe0_ne=-0.589207      !HOMO(Ne)/PBE0
ip_ar=0.5792                    !exp. ionisation potential
ip_ne=0.7925                    !exp. ionisation potential
shift_ar=ip_ar+eps_homo_pbe0_ar !shift for bulk xc potential (Ar)
shift_ne=ip_ne+eps_homo_pbe0_ne !shift for bulk xc potential (Ne)

!monomer A, perform LPBE0AC calculation
dummy,ar
{df-ks,pbex,pw91c,lhf; dftfac,0.75,1.0,0.25; asymp,shift_ne; save,$ca}
sapt;monomerA

!monomer B, perform LPBE0AC calculation
dummy,ne
{df-ks,pbex,pw91c,lhf; dftfac,0.75,1.0,0.25; start,atdens; asymp,shift_ar; save,$cb}
sapt;monomerB

!interaction contributions
{sapt,SAPT_LEVEL=3;intermol,ca=$ca,cb=$cb,icpks=0,fitlevel=3,nlexfac=0.0
dfit,basis_coul=jkfit,basis_exch=jkfit,cfit_scf=3}

!add high-order approximation to obtain the total interaction energy
eint_dftsapt=e12tot+delta_hf
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