Atomic start guess¶
Initial SCF run¶
We consider the Hartree-Fock calculation of plutonium dioxide cluster
In order to help convergence we will employ an atomic start.
Preparing the atomic start¶
For each atom we run a SCF calculation in full (linear) symmetry based on the atomic ground state configuration. For open-shell atoms this amounts to an average-of-configuration (AOC) calculation at the HF level, and a fractional occupation calculation at the DFT level.
Hydrogen atom¶
We run the hydrogen atom as a one-electron system. The input file H.inp accordingly reads:
**DIRAC
.WAVE FUNCTION
.ANALYZE
**GENERAL
.ACMOUT
**HAMILTONIAN
.ONESYS
**WAVE FUNCTIONS
.SCF
*SCF
.CLOSED SHELL
2 0
**ANALYZE
.MULPOP
*END OF
The molecular input H.mol is
BASIS
C 1 A
1. 1
H 0.0000000000 0.0000000000 0.0000000000
LARGE BASIS cc-pVDZ
FINISH
We run pam
pam --inp=H.inp --mol=H.mol --get=ACMOUT
mv DFACMO ac.H
Oxygen atom¶
The input file O.inp reads:
**DIRAC
.WAVE FUNCTION
.ANALYZE
**GENERAL
.ACMOUT
**WAVE FUNCTIONS
.SCF
*SCF
.CLOSED SHELL
4 0
.OPEN SHELL
1
4/0,6
**ANALYZE
.MULPOP
*END OF
The molecular input O.mol is
BASIS
C 1 A
8. 1
O 0.0000000000 0.0000000000 0.0000000000
LARGE BASIS cc-pVDZ
FINISH
We run the calculation
pam --inp=O.inp --mol=O.mol --get=DFACMO
mv DFACMO ac.O
Plutonium atom¶
For plutonium we employ the \([Rn]5f^4\) configuration of the \(Pu^{4+}\) cation. The input file Pu.inp accordingly reads:
**DIRAC
.WAVE FUNCTION
.ANALYZE
**GENERAL
.ACMOUT
**WAVE FUNCTIONS
.SCF
*SCF
.CLOSED SHELL
42 44
.OPEN SHELL
1
4/0,14
**INTEGRALS
*READIN
.UNCONTRACT
**ANALYZE
.MULPOP
*END OF
The molecular file ‘Pu.mol’ reads
BASIS
C 1 A
94. 1
Pu 0.0000000000 0.0000000000 0.0000000000
LARGE BASIS dyall.v2z
FINISH
We run the calculation
pam --inp=Pu.inp --mol=Pu.mol --get=DFACMO
mv DFACMO ac.Pu
Running the atomic start¶
We are now ready to run the atomic start. The input file ‘PuO2.inp’ reads:
**DIRAC
.WAVE FUNC
.ANALYZE
#.INPTES
**WAVE FUN
.SCF
*SCF
.ATOMST
AFPUXX 2
1..43
1.00
44..50
0.286
AFOXXX 2
1,2
1.00
3..5
0.667
AFHXXX 1
1
0.50
.CLOSED SHELL
84 86
**ANALYZE
.MULPOP
**END OF
The keyword ATOMST is followed by input for each atomic type. The occupations chosen corresponds to those of the atomic runs, but the user may modify this at will. Please note that the order of atoms corresponds to the order they appear in the molecule file. The molecular input file ‘PuO2.mol’ reads:
DIRAC
C 3 0 A
94. 1
Pu 0.0000000000 0.0000000000 0.0000000000
LARGE BASIS dyall.v2z
8. 8
O 1.3490000000 1.3490000000 1.3490000000
O 1.3490000000 1.3490000000 -1.3490000000
O -1.3490000000 1.3490000000 1.3490000000
O -1.3490000000 1.3490000000 -1.3490000000
O 1.3490000000 -1.3490000000 1.3490000000
O 1.3490000000 -1.3490000000 -1.3490000000
O -1.3490000000 -1.3490000000 1.3490000000
O -1.3490000000 -1.3490000000 -1.3490000000
LARGE BASIS cc-pVDZ
0.5 24
H 1.9263502692 0.7716497308 1.9263502692
H 1.9263502692 0.7716497308 -1.9263502692
H -1.9263502692 0.7716497308 1.9263502692
H -1.9263502692 0.7716497308 -1.9263502692
H 1.9263502692 -0.7716497308 1.9263502692
H 1.9263502692 -0.7716497308 -1.9263502692
H -1.9263502692 -0.7716497308 1.9263502692
H -1.9263502692 -0.7716497308 -1.9263502692
H 1.9263502692 1.9263502692 0.7716497308
H 1.9263502692 1.9263502692 -0.7716497308
H -1.9263502692 1.9263502692 0.7716497308
H -1.9263502692 1.9263502692 -0.7716497308
H 1.9263502692 -1.9263502692 0.7716497308
H 1.9263502692 -1.9263502692 -0.7716497308
H -1.9263502692 -1.9263502692 0.7716497308
H -1.9263502692 -1.9263502692 -0.7716497308
H 0.7716497308 1.9263502692 1.9263502692
H 0.7716497308 1.9263502692 -1.9263502692
H -0.7716497308 1.9263502692 1.9263502692
H -0.7716497308 1.9263502692 -1.9263502692
H 0.7716497308 -1.9263502692 1.9263502692
H 0.7716497308 -1.9263502692 -1.9263502692
H -0.7716497308 -1.9263502692 1.9263502692
H -0.7716497308 -1.9263502692 -1.9263502692
LARGE BASIS cc-pVDZ
#SMALL KINBAL
FINISH
Before running the calculation the user must make provide links to the atomic coefficient files
ln -s ac.Pu AFPUXX
ln -s ac.C AFCXXX
ln -s ac.H AFHXXX
and the calculation was then run as
pam --mol=PuO2.mol --inp=PuO2.inp --copy="AF*" --outcmo --mw=105 --mpi=32
This calculation converges smoothly after 9 iterations
SCF - CYCLE
-----------
* Convergence on norm of error vector (gradient).
Desired convergence:1.000D-07
Allowed convergence:1.000D-06
* ERGVAL - convergence in total energy
* FCKVAL - convergence in maximum change in total Fock matrix
* EVCVAL - convergence in error vector (gradient)
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Energy ERGVAL FCKVAL EVCVAL Conv.acc CPU Integrals Time stamp
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It. 1 -30262.16062810 3.03D+04 0.00D+00 0.00D+00 Atomic s 8min27.160s LL SL Sun Dec 2
It. 2 -29246.11569530 -1.02D+03 -4.18D+01 1.15D+01 18min50.650s LL SL Sun Dec 2
It. 3 -29248.64080628 2.53D+00 4.35D+00 5.49D+00 DIIS 2 18min31.760s LL SL Mon Dec 3
It. 4 -29248.86829228 2.27D-01 -1.32D+00 2.81D-01 DIIS 3 17min35.410s LL SL Mon Dec 3
It. 5 -29248.86879546 5.03D-04 3.32D-02 3.76D-02 DIIS 4 16min51.240s LL SL Mon Dec 3
It. 6 -29248.86880842 1.30D-05 8.21D-03 8.29D-04 DIIS 5 15min15.820s LL SL Mon Dec 3
It. 7 -29248.86880842 3.88D-09 -5.99D-05 5.49D-05 DIIS 6 13min26.070s LL SL Mon Dec 3
It. 8 -29248.86880843 3.43D-09 8.30D-06 1.55D-06 DIIS 7 11min31.390s LL SL Mon Dec 3
It. 9 -29248.86880842 -7.49D-10 -1.04D-06 4.71D-08 DIIS 7 9min 3.550s LL SL Mon Dec 3
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