[molpro-user] CaF ground state HF and UHF calculation problems with Molpro2015.1.8

[Peterson, Kirk]

Dear Dr. Hou,

I’m not sure if this is the problem, but starting from long range and working inwards is sometimes not the best idea for ionic molecules.  Also for open shell systems, often one should really completely specify the wavefunction using occ, closed, and wf directives.  See my example below.

regards,

-Kirk



***, CaF
memory,100,m

print orbitals

basis={
default,vdz
F=avdz
}

r=[3.0,3.2,3.4,3.5,3.6,3.7,3.75,3.8,3.9,4.0]

geom={
Ca
F 1 r(i)}

do i=1,#r

{hf;occ,9,3,3;closed,8,3,3;wf,29,1,1}
eval(i)=energy

enddo

table,r,eval
digit,2,7
---



On Nov 16, 2016, at 4:28 AM, 侯世林 <slhou at ouc.edu.cn<mailto:slhou at ouc.edu.cn>> wrote:

Dear all:

I have some troubles when calculating CaF with HF and UHF method, and this will consequently influence the results of the related post-HF approaches. I use the version of Molpro 2015.1.8.
Both HF and UHF can do optimization successfully and give reasonable results. However, when a set of internuclear separations R are given, the UHF can finish calculations with no computational errors but the final results are wrong, because the obtained potential curve is repulsive for CaF ground state.
With HF method, reasonable results can be obtained only for the first R, and then the following error message present:

' Molecular orbitals read from record     2100.2  Type=RHF/CANONICAL (state 1.1)
 Incorrect occupation. noc=  15  ncl=  15  nelec=  29  ms2= 1
 ICLOS
   1-  8     9     3     3     0     0     0     0     0
 NOCC
   1-  8     9     3     3     0     0     0     0     0
'
The input file for HF calculation reads

   r=[25.0 18.0 ... ]
   geometry={F;Ca,F,$r(l)}
    basis=v5z; F=av5z
do l=1,#r
     HF

    e(1) = energy
    method(1) = program
    dip(1) = dmz
    bond(1) = $r(l)

   table,method,bond,e,dip
enddo


For UHF, the 'HF' is just replaced with 'UHF', the output data in units a.u. are:  .
 METHOD     BOND        E            DIP
 UHF-SCF   25.00   -775.9654195   -0.00017432
 UHF-SCF   18.00   -775.9653928   -0.00069340
 UHF-SCF   12.00   -775.9652089   -0.00390148
 UHF-SCF   11.50   -775.9651646   -0.00469214
 UHF-SCF   11.00   -775.9651097   -0.00568491
 UHF-SCF   10.50   -775.9650412   -0.00694651
 UHF-SCF   10.00   -775.9649553   -0.00857887
 UHF-SCF    9.50   -775.9648472   -0.01069510
 UHF-SCF    9.00   -775.9647107   -0.01349033
 UHF-SCF    8.50   -775.9645376   -0.01720938
 UHF-SCF    8.00   -775.9643176   -0.02216390
 UHF-SCF    7.50   -775.9640366   -0.02871871
 UHF-SCF    7.00   -775.9636746   -0.03732960
 UHF-SCF    6.50   -775.9632006   -0.04848223
 UHF-SCF    6.00   -775.9625529   -0.06287766
 UHF-SCF    5.80   -775.9622145   -0.06969148
 UHF-SCF    5.60   -775.9618031   -0.07716052
 UHF-SCF    5.00   -775.9596775   -0.10355852
 UHF-SCF    4.50   -775.9551436   -0.12986174
 UHF-SCF    4.20   -775.9491519   -0.14710620
 UHF-SCF    4.00   -775.9423734   -0.15892108
 UHF-SCF    3.90   -775.9376989   -0.16481988
 UHF-SCF    3.80   -775.9318805   -0.17064276
 UHF-SCF    3.75   -775.9284576   -0.17349700
 UHF-SCF    3.70   -775.9246395   -0.17630598
 UHF-SCF    3.60   -775.9156343   -0.18171688
 UHF-SCF    3.50   -775.9044483   -0.18673182
 UHF-SCF    3.40   -775.8905774   -0.19116755
 UHF-SCF    3.20   -775.8522514   -0.19723968
 UHF-SCF    3.00   -775.7944646   -0.19696011

The UHF optimization result is:
      R               E1          DIP1
    3.73815213   -776.3297329   1.07225773

The HF optimization result is:
 METHOD     BOND            E           DIP
 HF-SCF   3.73818011   -776.3296065   1.06723713

How to solve such problems?

Thank you!

Dr. Shilin HOU

Department of Physics,
Ocean University of China
238 Songling Road, Qingdao,
Shandong, 266100_______________________________________________
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