problem with orbital localization in aromatic systems

[Richard Christie]

Dear MOLPRO user community,

I am experiencing difficulties in obtaining "correct" localized orbitals
for aromatic systems when using basis sets including diffuse
functions. For example, with the aug-cc-pVDZ basis set, the localized
pi orbitals in benzene include functions from the hydrogen atoms. This
happens with both the Boys and Pipek-Mezey localization procedures. In 
the case of benzene, this problem can be "solved" by dropping back to the
cc-pVDZ basis set on the Hydrogen atoms. But, for other molecules,
e.g. indole, this does not fix the problem. An example of a truncated
output for benzene illustrating the problem is appended. Immediately
following the output is the input file and an input file for indole.

Yours Sincerely,
Richard Christie

----------------------------------------------------------------------------

*** MOLPRO OUTPUT **** (Input file is appended to this message)

 Local correlation treatment
 ===========================

 LOCAL=4     IBASO= 0     IDLEIG=1     IDLCOR=2     WEAKP= 1.00 DISTP=.00
DRANGE=  .00
 MAXL=0      DELSHL= 1   SKIPD=3     LOCSNG=0     LOCMUL=1     MERGEDOM=1
THRLOC=1.00D-06
 THRORB=1.00D-06   CDELMIN= .10   SELECT=0   NONORM= 0

 Orbital domain selection criteria:

 CHGFRAC= .980   CHGMIN= .010   CHGMINH= .030
 .
 .
 .
  Merged orbital domains

   Orb.   Atoms
   7.1    1 C    2 C    3 C    4 C    5 C    6 C    9 H   10 H   11 H
   8.1    1 C    3 C    4 C    5 C    6 C   10 H   11 H   12 H
   9.1    1 C    2 C    3 C    4 C    5 C    8 H    9 H   10 H
  12.1    1 C    2 C    3 C    4 C    5 C    6 C    8 H    9 H   10 H   11 H
         12 H
  15.1    1 C    2 C    3 C    4 C    5 C    6 C    7 H    8 H   10 H   11 H
         12 H
  16.1    1 C    2 C    3 C    4 C    5 C    6 C    7 H    8 H    9 H   10 H
         12 H
  19.1    1 C    2 C    3 C    4 C    5 C    6 C    7 H   11 H   12 H
  20.1    1 C    2 C    3 C    4 C    5 C    6 C    7 H    8 H    9 H
  21.1    1 C    2 C    3 C    5 C    6 C    7 H    8 H   12 H

*** END OF OUTPUT ***       

----------------------------------------------------------------------------

*** MOLPRO INPUT FOR BENZENE ***

 ***, LMP2 Test1
 memory,260,m
 gdirect,page=1;
 geomtyp=xyz
 geometry={nosym;noorient;angstroms;
 12
 Benzene-W1 geometry
 C        .000000     .000000    1.399100
 C       1.211656     .000000     .699550
 C       1.211656     .000000    -.699550
 C        .000000     .000000   -1.399100
 C      -1.211656     .000000    -.699550
 C      -1.211656     .000000     .699550
 H        .000000     .000000    2.486500
 H       2.153372     .000000    1.243250
 H       2.153372     .000000   -1.243250
 H        .000000     .000000   -2.486500
 H      -2.153372     .000000   -1.243250
 H      -2.153372     .000000    1.243250
 }
 basis=aVDZ
 hf;
 locali,pipek;
 mp2;local,MERGEDOM=1;

---                                                     
----------------------------------------------------------------------

*** MOLPRO INPUT FOR INDOLE ***

***, LMP2 Test2
memory,260,m
gdirect,page=1;
geomtyp=xyz
geometry={nosym;noorient;angstrom;
  16
  LMP2 TEST1
C1         -3.0902605896        -.6674460262        -.3513398001
C1        -2.2419333821       -1.7262974587         .0109820682
C1          -.9229107582       -1.4957444790         .3389470877
C1          -.4344922487        -.1864165925         .3063763073
C1         -1.2991003716         .8588148401        -.0587914076
C1         -2.6333881999         .6328674636        -.3911625225
H2         -4.1128319287        -.8760455322        -.6014425214
H2         -2.6312616696       -2.7259583694         .0316573291
H2          -.2798558086       -2.3095098114         .6160724034
H2         -3.2841077178        1.4406292291        -.6675476913
C3           .7227498403        1.7423990039         .3774759757
N4          -.5735591472        2.0301877509        -.0094299145
H2          -.9206081357        2.9326527489        -.2163701375
H2          1.4471701387        2.5194201851         .4759714876
C3           .8519046472         .4111885982         .5794198263
H2          1.7395453313        -.0978315505         .8835015097
}
!
BASIS
SET=ORBITAL
DEFAULT=aVDZ
2=VDZ
END
hf;
locali,pipek;
mp2;local,MERGEDOM=1;
                                
---------------------------------------------------------------------

-- 
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richard christie
box 90 chevron science centre		tel: 412-624-8694
university of pittsburgh
pittsburgh
PA 15260
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