[molpro-user] Making SCF converge to the ground state
werner at theochem.uni-stuttgart.de
Tue May 15 20:55:37 BST 2007
by default Molpro freezes the occupations after a certain number of iterations,
and if at this stage the occuation happens to be wrong it will converge to
the excited state. This can be controlled by the parameter NITORD.
Try, e.g., rhf,nitord=50!
(i) don't confuse NITORD (refers to "order" with parameter NITORT (refers to "orthogonalization")
(ii) Note that in a restart from previous orbitals the occupations are frozen from
the beginning unless NITORD is specified. It should also be possible to
use rotate,1.2,2.2 in a second rhf calculation.
If nothing helps, please send the input and I'll take a look!
On Di, 15 Mai 2007, Terry Frankcombe wrote:
>I've been running into a problem with my HF orbital occupations quite a
>lot recently. I'm trying to do calculations on a triplet system, but
>the SCF program insists on converging to a state that isn't the ground
>The problem is illustrated by the following output from a dump to a
> DUMP ORBITAL 1.1 AS ORBITAL 1 occ= 2.0000 eig= -15.6686
> DUMP ORBITAL 2.1 AS ORBITAL 2 occ= 2.0000 eig= -15.6633
> DUMP ORBITAL 3.1 AS ORBITAL 3 occ= 2.0000 eig= -11.3487
> DUMP ORBITAL 4.1 AS ORBITAL 4 occ= 2.0000 eig= -1.2977
> DUMP ORBITAL 5.1 AS ORBITAL 5 occ= 2.0000 eig= -0.9600
> DUMP ORBITAL 6.1 AS ORBITAL 6 occ= 2.0000 eig= -0.6882
> DUMP ORBITAL 7.1 AS ORBITAL 7 occ= 2.0000 eig= -0.5551
> DUMP ORBITAL 8.1 AS ORBITAL 8 occ= 2.0000 eig= -0.5302
> DUMP ORBITAL 1.2 AS ORBITAL 9 occ= 2.0000 eig= -0.4495
> DUMP ORBITAL 2.2 AS ORBITAL 10 occ= 1.0000 eig= -0.6223
> DUMP ORBITAL 9.1 AS ORBITAL 11 occ= 1.0000 eig= -0.5463
>The energy of the singly occupied orbital 2.2 is lower than the doubly
>occupied orbitals 7.1, 8.1 and 1.2! The chemistry agrees that this is
>wrong and that the second unpaired spin should be orbital 1.2, mostly
>localised to the same atom as 9.1 (on an incoming nitrogen atom). The
>calculated SCF energy is about 0.3 hartree higher than it should be.
>CASSCF calculations give the correct state and energy, with the second
>electron "excited" out of that 1.2 orbital.
>I've played quite a bit with orbital shifts and the initial guess, to no
>avail. How can I convince Molpro that a singly occupied orbital deep in
>the spectrum is wrong?
>Dr Terry Frankcombe
>Physical Chemistry, Department of Chemistry
>SE-412 96 Göteborg Sweden
>Ph: +46 76 224 0887 Skype: terry.frankcombe
><terry at chem.gu.se>
Prof. Hans-Joachim Werner
Institute for Theoretical Chemistry
University of Stuttgart
D-70569 Stuttgart, Germany
Tel.: (0049) 711 / 685 64400
Fax.: (0049) 711 / 685 64442
e-mail: werner at theochem.uni-stuttgart.de
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