[molpro-user] C2v symmetry for atom with two dummy atoms

[Paul Jerabek]

Dear Molpro users,

I'm doing counterpoise corrections on an equilateral trimer. For that,
I'm computing the energies of the trimer, the dimer with one dummy atom
and the monomer with two dummy atoms.

I'd like to utilize C2v symmetry and can get it to work with the trimer
and the dimer (if I'm using ORIENT, CHARGE).

However, for the monomer with two dummy atoms, I fail.

----------------------------
----------------------------
Ar Monomer calculation:
----------------------------
----------------------------
memory,125,m
basis=def2-SVP

rab = [3.8]
rac = [3.8]
rbc = [3.8]

alpha = [60.0]

ORIENT, CHARGE
SYMMETRY, X,Y

i=1
geometry={
          Ar1;
          Ar2,Ar1,rab(i);
          Ar3, Ar1,rac(i),Ar2,alpha(i)}

text, A monomer, B,C ghost atom
dummy, ar2, ar3
do i=1,#rab
  {hf; maxit, 400}     ;e_ar_br_cg_hf(i)=energy             ! HF
enddo
----------------------
Output:

 Orientation using atomic charges
 Molecule type: Symmetric top,     Order of principal axis = 3
 User-specified symmetry elements: X,Y
 Symmetry elements: X,Y

 Point group  C2v



 ATOMIC COORDINATES

 NR  ATOM    CHARGE       X              Y              Z

   1  AR1    18.00    0.000000000    0.000000000   -2.193931023
   2  AR2     0.00    0.000000000   -1.900000000    1.096965511
   3  AR3     0.00    0.000000000    1.900000000    1.096965511

 Bond lengths in Bohr (Angstrom)

 1-2  3.800000000  1-3  3.800000000  2-3  3.800000000
     ( 2.010873401)     ( 2.010873401)     ( 2.010873401)

 Bond angles

  1-2-3   60.00000000   1-3-2   60.00000000   2-1-3   60.00000000

 NUCLEAR CHARGE:                   18
 NUMBER OF PRIMITIVE AOS:         111
 NUMBER OF SYMMETRY AOS:          108
 NUMBER OF CONTRACTIONS:           54   (  22A1  +   9B1  +  17B2  +
6A2  )
 NUMBER OF CORE ORBITALS:           5   (   3A1  +   1B1  +   1B2  +
0A2  )
 NUMBER OF VALENCE ORBITALS:        4   (   2A1  +   1B1  +   1B2  +
0A2  )


 NUCLEAR REPULSION ENERGY    0.00000000

 *** Symmetry of molecule has changed ***
 ? Error
 ? Geometry: cannot have a symmetric top with unique axis x
 ? The problem occurs in zmatrix.f
    0: fehler 1 (0x1).
    0: In mpi_utils.cpp [MPIGA_Error]: now exiting...
----------------------------
----------------------------


Obviously, if I repeat the calculation with real, but different atoms,
everything works fine.


----------------------------
----------------------------
Test Trimer calculation:
----------------------------
----------------------------
memory,125,m

basis=def2-SVP

rab = [3.8]
rac = [3.8]
rbc = [3.8]

alpha = [60.0]

ORIENT, CHARGE
SYMMETRY, X,Y

i=1
geometry={
          Ar1;
          Kr2, Ar1,rab(i);
          Kr3, Ar1,rac(i),Kr2,alpha(i)}

text, A monomer, B,C ghost atom
do i=1,#rab
  {hf; maxit, 400}     ;e_ar_br_cg_hf(i)=energy             ! HF
enddo

----------------------
Output:

Orientation using atomic charges
 Molecule type: Asymmetric top,     Order of principal axis = 2
 User-specified symmetry elements: X,Y
 Symmetry elements: X,Y

 Point group  C2v



 ATOMIC COORDINATES

 NR  ATOM    CHARGE       X              Y              Z

   1  AR1    18.00    0.000000000    0.000000000   -2.632717228
   2  KR2    36.00    0.000000000   -1.900000000    0.658179307
   3  KR3    36.00    0.000000000    1.900000000    0.658179307

 Bond lengths in Bohr (Angstrom)

 1-2  3.800000000  1-3  3.800000000  2-3  3.800000000
     ( 2.010873401)     ( 2.010873401)     ( 2.010873401)

 Bond angles

  1-2-3   60.00000000   1-3-2   60.00000000   2-1-3   60.00000000

 NUCLEAR CHARGE:                   90
 NUMBER OF PRIMITIVE AOS:         197
 NUMBER OF SYMMETRY AOS:          184
 NUMBER OF CONTRACTIONS:           82   (  31A1  +  14B1  +  26B2  +
11A2  )
 NUMBER OF CORE ORBITALS:          33   (  13A1  +   5B1  +  11B2  +
4A2  )
 NUMBER OF VALENCE ORBITALS:       12   (   5A1  +   2B1  +   4B2  +
1A2  )


 NUCLEAR REPULSION ENERGY  682.10526316


 Eigenvalues of metric

         1 0.232E-01 0.106E+00 0.180E+00 0.221E+00 0.246E+00 0.331E+00
0.352E+00 0.358E+00
         2 0.237E+00 0.300E+00 0.362E+00 0.369E+00 0.624E+00 0.812E+00
0.935E+00 0.963E+00
         3 0.141E-01 0.112E+00 0.154E+00 0.251E+00 0.270E+00 0.288E+00
0.333E+00 0.410E+00
         4 0.197E+00 0.297E+00 0.330E+00 0.556E+00 0.804E+00 0.862E+00
0.102E+01 0.117E+01
----------------------------
----------------------------

I tried out different combination of symmetry elements and orientations,
but couldn't get it to work properly.

Does somebody have good advice on what I'm doing wrong?

Thanks in advance!

Best regards,

	Paul

-- 
Dr. Paul Jerabek
Schwerdtfeger Group, Centre for Theoretical Chemistry and Physics
Bob Tindall Bldg., NZ Institute for Advanced Study
Massey University (Albany Campus)
Private Bag 102904
North Shore MSC, Auckland
New Zealand
Phone +64 9 414 0800 ext. 41698