Dear all,

A BAD FIT message can occur if relativistic options
are used with the wrong basis sets.
What can go terribly wrong is a relativistic Pauli
calculation with a ZORA basis set.
Such a calculation is of no use.

Recommendation:
Use ZORA fozen core basis sets only in ZORA calculations.
All electron basis sets can always be used both in ZORA as well as in
non-relativistic calculations
(they may be more optimal for either ZORA or non-relativistic calculations)
If the Pauli Hamitonian is used
then use the non-relativistic basis sets, and for the heavier elements
use only the frozen core basis sets in the non-relativistic basis sets.
See also the ADFUserGuide, and the README in the atomicdata base directory
(latest ADF-version).
Recommendation, use ZORA instead of the Pauli Hamiltonian.

An example when things can go terribly wrong is:
 $ADFBIN/dirac -n1 < $ADFRESOURCES/Dirac/W.4f
 mv TAPE12 t12

 $ADFBIN/adf -n1 << eor
 Create W $ADFRESOURCES/ZORA/TZP/W.4f
 relativistic scalar
 corepotentials t12 &
 W 1
 end
 end input
 eor

This will give as output:
Orbital Energies, all Irreps
 ========================================

 Irrep no. (spin) Occup E (au) E (eV)
 ---------------------------------------------------------------------------
 S 1 2.00 -0.20216706646073E+05 -550124.8029
 S 2 2.00 -0.22087256639084E+01 -60.1025
 P 1 6.00 -0.12463899830030E+01 -33.9160
 S 3 0.00 -0.20876809555667E+00 -5.6809
 D 1 4.00 -0.11351816597052E+00 -3.0890
 
In the S-space there is variational collapse, due to the
used Pauli Hamiltonian with the wrong basis set.

Correct example:
 $ADFBIN/dirac -n1 < $ADFRESOURCES/Dirac/W.4f
 mv TAPE12 t12

 $ADFBIN/adf -n1 << eor
 Create W $ADFRESOURCES/ZORA/TZP/W.4f
 relativistic scalar zora
 corepotentials t12 &
 W 1

 end
 end input
 eor

 Orbital Energies, all Irreps
 ========================================

 Irrep no. (spin) Occup E (au) E (eV)
 ---------------------------------------------------------------------------
 S 1 2.00 -0.28951954354516E+01 -78.7823
 P 1 6.00 -0.15921507270829E+01 -43.3246
 S 2 2.00 -0.21603628791271E+00 -5.8786
 D 1 4.00 -0.17227556379942E+00 -4.6879

Best regards,
Erik van Lenthe

----------------------------------------------------------------------
Dr. Erik van Lenthe SCIENTIFIC COMPUTING & MODELLING NV
Tel: +31 20 44 47615 Vrije Universiteit, Theoretische Chemie
secretary: 44 47519 De Boelelaan 1083
 fax: 44 47629 1081 HV Amsterdam, The Netherlands
 e-mail: vanlenthe@scm.com http://www.scm.com
----------------------------------------------------------------------
Received on 2002-12-17 16:31:40