[molpro-user] energy gradients

Alexander Mitrushchenkov sasha at theochem.uni-stuttgart.de
Thu Jul 19 14:05:07 BST 2007


Dear Jeremy,

We considered in detail the bug raised by you (1411). First, you should not 
use nomodel option as it slows down the convergence considerably. Second, we 
were unable to reproduce NaNs you mentioned, maybe you can give more detail 
about molpro version, patch level, platform and compiler you were using. 
Next, I investigated the problem of numerical gradients and found that the 
default values for steps produce not accurate enough gradients leading to 
slow and wrong convergence. Note that the default 'optg' converge nicely. If 
you wish to use numerical gradients, you should reduce steps to say 0.001 for 
distances and 0.1 for angles, and use 4-point formulae for derivatives. Then 
it gives exactly the same answer as analytic gradients. Most probably, your 
system is highly anharmonic. With this, I close bug 1411.

Best wishes,

Sasha

On Wednesday 09 May 2007 17:54, Jeremy Merritt wrote:
> Dear Molpro Users,
> For some reason I cant get my frequency calculation to calculate the
> forces numerically.  Instead it defaults to the alaska program to
> calculate the gradients which also fails.
> Note the geometry optimization works fine using the numerical gradients,
> but the analytical gradients also fail. In the molpro manual it says
> that analytical gradients should be available for RKS so i'm not sure
> what is going wrong. I'm using version 2006.1
> Any help would be appreciated.
>
> My input is for the C6H5 radical:
> basis={
> !
> !  Literature Citation
> !Elements
> References
> !--------
> ----------
> ! H     : T.H. Dunning, Jr. J. Chem. Phys. 90, 1007
> (1989).
> ! He    : D.E. Woon and T.H. Dunning, Jr. J. Chem. Phys. 100, 2975
> (1994).
> !Li - Ne: T.H. Dunning, Jr. J. Chem. Phys. 90, 1007
> (1989).
> !Na - Mg: D.E. Woon and T.H. Dunning, Jr.  (to be
> published)
> !Al - Ar: D.E. Woon and T.H. Dunning, Jr.  J. Chem. Phys. 98, 1358
> (1993).
> !Ca     : J. Koput and K.A. Peterson, J. Phys. Chem. A, 106, 9595
> (2002).
> !
> !  POLARIZATION AND/OR DIFFUSE FUNCTIONS
> !Elements
> References
> !--------
> ---------
> ! H    :  T.H. Dunning, Jr. J. Chem. Phys. 90, 1007
> (1989).
> ! He   :  D.E. Woon and T.H. Dunning, Jr., J. Chem. Phys. 100, 2975
> (1994).
> ! B - F:  R.A. Kendall, T.H. Dunning, Jr. and R.J. Harrison, J. Chem.
> Phys. 96,
> !         6769
> (1992).
> !Al - Cl: D.E. Woon and T.H. Dunning, Jr. J. Chem. Phys. 98, 1358
> (1993).
> !
> ! HYDROGEN     (4s,1p) -> [2s,1p]
> ! HYDROGEN     Diffuse (1s,1p)
> s,H
> ,0.130100000E+02,0.196200000E+01,0.444600000E+00,0.122000000E+00,0.29740000
>0E-01 c,1.4, 0.196850000E-01, 0.137977000E+00, 0.478148000E+00,
> 0.501240000E+00 c,4.4, 0.100000000E+01
> c,5.5, 0.100000000E+01
> p,H ,0.727000000E+00,0.141000000E+00
> c,1.1, 0.100000000E+01
> c,2.2, 0.100000000E+01
> !
> ! CARBON       (9s,4p,1d) -> [3s,2p,1d]
> ! CARBON       Diffuse (1s,1p,1d)
> s,C
> ,0.666500000E+04,0.100000000E+04,0.228000000E+03,0.647100000E+02,0.21060000
>0E+02,0.749500000E+01,0.279700000E+01,0.521500000E+00,0.159600000E+00,0.4690
>00000 E-01
> c,1.9, 0.692000000E-03, 0.532900000E-02, 0.270770000E-01,
> 0.101718000E+00, 0.274740000E+00, 0.448564000E+00, 0.285074000E+00,
> 0.152040000E-01,-0.319100000E-02
> c,1.9,-0.146000000E-03,-0.115400000E-02,-0.572500000E-02,-0.233120000E-01,-
>0.639550000E-01,-0.149981000E+00,-0.127262000E+00, 0.544529000E+00,
> 0.580496000E+00
> c,9.9, 0.100000000E+01
> c,10.10, 0.100000000E+01
> p,C
> ,0.943900000E+01,0.200200000E+01,0.545600000E+00,0.151700000E+00,0.40410000
>0E-01 c,1.4, 0.381090000E-01, 0.209480000E+00, 0.508557000E+00,
> 0.468842000E+00 c,4.4, 0.100000000E+01
> c,5.5, 0.100000000E+01
> d,C ,0.550000000E+00,0.151000000E+00
> c,1.1, 0.100000000E+01
> c,2.2, 0.100000000E+01
> }
>
>   rCH1 = 1.09120546
>    rCH2 = 1.09162863
>    rCH3 = 1.09089510
>    rCC1 = 1.39879138
>    rCC2 = 1.40815682
>    R = 2.71902477
>    aHCC1 = 119.33852066
>    aHCC2 = 120.33442982
>    aHCC3 = 119.84978525
>    aHCC4 = 121.17053159
>
>    geometry={X,Y,ANGSTROM,
>    C4,
>    X, C4, 1.0,
>    H3, C4, rCH1, X, 90.0,
>    C3, C4, rCC1, H3, aHCC1, X, 180.0,
>    C5, C4, rCC1, H3, aHCC1, X, 0.0,
>    H2, C3, rCH2, C4, aHCC2, H3, 0.0,
>    H4, C5, rCH2, C4, aHCC2, H3, 0.0,
>    C2, C3, rCC2, H2, aHCC3, H3, 180.0,
>    C6, C5, rCC2, H4, aHCC3, H3, 180.0,
>    H1, C2, rCH3, C3, aHCC4, H3, 180.0,
>    H5, C6, rCH3, C5, aHCC4, H3, 180.0,
>    C1, C4, R, X, 90.0, H3, 180.0,
>    }
>
>     {RKS,B3LYP
>      wf,41,1,1,0}
>     {optg,numerical
>      Hessian,nomodel}
>     {Frequencies,NUMERICAL,SYMM=AUTO;}
>     put,molden,C6H5.mol
>
> *selected output from the log file:
> *
> 1PROGRAM * ALASKA (Gradient of the energy)     Author: R. Lindh
>
>  Orbitals from record         2100.1
>
>  Number of closed-shell orbitals: 20 ( 17  3 )
>  Number of active orbitals:        1 (  1  0 )
>  Number of occupied orbitals:     21 ( 18  3 )
>
>  Number of electrons= 41     Doublet     Space symmetry=1
> Wavefunction type: OSCF
>
>
>  DFT GRADIENT, EXFAC=      .200
>
>  RKS GRADIENT FOR STATE 1.1
>
>  Atom          dE/dx               dE/dy               dE/dz
>
>    1          .000000000                NaNQ                NaNQ
>    2          .000000000                NaNQ                NaNQ
>    3          .000000000                NaNQ                NaNQ
>    4          .000000000                NaNQ                NaNQ
>    5          .000000000                NaNQ                NaNQ
>    6          .000000000                NaNQ                NaNQ
>    7          .000000000                NaNQ                NaNQ
>    8          .000000000                NaNQ                NaNQ
>    9          .000000000                NaNQ                NaNQ
>   10          .000000000                NaNQ                NaNQ
>   11          .000000000                NaNQ                NaNQ
>
>  Starting task   7.  CPU=  2201.10 sec, Elapsed=  2273.53 sec
>  Incrementing variable H3Z2             by   .010000 BOH   to
> 4.619076 BOH

-- 
Dr. Alexander Mitrushchenkov

Universität Stuttgart
Institut für Theoretische Chemie
Pfaffenwaldring 55
D-70569 Stuttgart

Tel +49 (0)711 / 685-64409
Fax +49 (0)711 / 685-64442
Mail sasha at theochem.uni-stuttgart.de




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