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Masoud Nahali
masoudnahali@gmail.com

I am studying the molecular oxygen adsorption on some surfaces; and in my input file the distance between the oxygen and the surface atoms is about 3.5 angstrom. I get the below error when I run the job :

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ERROR: BAD DELOCALIZED COORDINATES GENERATED!!!
       922 PRIMITIVE INTERNAL COORDINATES ARE BEING USED.
       361 LINEARLY INDEPENDENT COMBINATIONS OF THESE ARE FOUND.
       366 COORDINATES ARE NEEDED TO HAVE A TOTAL OF 3N-6.

IF THE NUMBER OF LINEARLY INDEPENDENT COOORDS IS TOO SMALL,
ADD SOME COORDINATES BY -NONVDW- TO CONNECT MONOMER PIECES
(ESPECIALLY IF YOU ARE SHORT BY A MULTIPLE OF 6), OR ELSE
USE -IXZMAT- TO ADD EXTRA PRIMITIVE COORDINATES.

IF THE NUMBER OF LINEARLY INDEPENDENT COOORDS IS TOO BIG,
TRY USING -IRZMAT- TO REMOVE SOME PRIMITIVE COORDINATES.
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It seems that I should connect the oxygen to the surface by NONVDW command but I could not find any documentation to guide me how to do it. How can I connect two atoms by NONVDW ? what is the physics of this work ?
Also, I do not want to enforce the oxygen to be adsorbed on some specified atoms (may be specified by NONVWD). Oxygen should choose any atoms through optimization procedure.

This is my input file commands :

$CONTRL SCFTYP=RHF RUNTYP=OPTIMIZE DFTTYP=B3LYP ECP=read MAXIT=350 MULT=1
ICHARG=0 COORD=unique d5=.t. NZVAR=366 $END
$SYSTEM TIMLIM=600000 MWORDS=200 $END
$SCF DIRSCF=.TRUE. NCONV=5 $END
$STATPT OPTTOL=0.0001 NSTEP=150 $END
$zmat dlc=.true. auto=.true. $end
! to activate P2P inteface and DLB:
$P2P P2P=.T. DLB=.T. $END
! to speed up Huckel guess:
$GUESS guess=HUCKEL $END
$smp call64=.t. mkl64=8 load=0 ssg32=0 msu32=0 mkllvl=3 $end
$BASIS gbasis=LANL2DZ extfil=.t. $END  

I appreciate your help in advance.

Best Wishes

Masoud
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Masoud Nahali, Sharif University of Technology